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THE
THEORY AND PRACTICE
OF
BREWING.
BY MICHAEL COMBRUNE, BREWER.
ORIGINALLY PUBLISHED WITH PERMISSION OF THE MASTER, WARDENS,
AND COURT OF ASSISTANTS OF THE WORSHIPFUL
COMPANY OF BREWERS.
A NEW EDITION.
CORRECTED AND GREATLY ENLARGED BY THE AUTHOR.
_LONDON_:
PRINTED FOR VERNOR AND HOOD, LONGMAN AND REES, CUTRELL
AND MARTIN, AND J. WALKER,
_By J. Wright, St. John’s Square, Clerkenwell_.
1804.
TO
DOCTOR PETER SHAW,
_PHYSICIAN TO HIS MAJESTY_,
FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS OF LONDON,
AND OF THE ROYAL SOCIETY.
SIR,
The brewing of malt liquors has hitherto been conducted by such vague
traditional maxims, that an attempt to establish its practice on truer
and more fixed principles must, like every new essay, be attended with
difficulties.
Your works, Sir, will be lasting monuments, not only of your great
abilities, but also of your zeal for the improvement of the arts,
manufactures, and commerce of your country. You will therefore permit
me to place under your patronage this treatise, which, if it can boast
no other merit, has that of having been undertaken and finished by your
advice and counsel.
Some favor, I hope, will be shewn for this distant endeavour to imitate
the laudable example you have set, and whatever be the success, I shall
ever glory in the opportunity it has given me of professing myself
publicly,
Sir,
Your most obedient,
And most obliged humble Servant,
MICHAEL COMBRUNE.
_Hampstead, Middlesex,
December 15, 1761._
THE
CONTENTS.
Page
PART I.
Explanation of technical terms, 1
SECTION I.
Of Fire, 13
SECTION II.
Of Air, 19
SECTION III.
Of Water, 24
SECTION IV.
Of Earth, 33
SECTION. V.
Of Menstruums or Dissolvents, 34
SECTION VI.
Of the Thermometer, 39
SECTION VII.
Of the Vine, its fruits, and juices, 50
SECTION VIII.
Of fermentation in general, 66
SECTION IX.
Of artificial fermentation, 80
SECTION X.
Of the nature of Barley, 89
SECTION XI.
Of Malting, 94
SECTION XII.
Of the different Properties of Malt, and of the number
of its fermentable Parts, 113
SECTION XIII.
Observations on defective Malts, 131
PART II.
SECTION I.
Of the heat of the Air, as it relates to the practical
part of Brewing, 145
SECTION II.
Of Grinding, 157
SECTION III.
Of Extraction, 160
SECTION IV.
Of the nature and properties of Hops, 201
SECTION V.
Of the lengths necessary to form malt liquors of the
several denominations, 217
SECTION VI.
Method of calculating the height in the Copper at
which worts are to go out, 220
SECTION VII.
Of Boiling, 224
SECTION VIII.
Of the quantity of Water wasted; and of the application
of the preceding rules to two different processes
of Brewing, 230
SECTION IX.
Of the division of the Water for the respective
Worts and Mashes, and of the heat adequate to
each of these, 234
SECTION X.
An enquiry into the volume of Malt, in order to reduce
the Grist to liquid measure, 253
SECTION XI.
Of the proportion of cold Water to be added to
that which is on the point of boiling, in order
to obtain the desired heat in the extract, 271
SECTION XII.
Of Mashing, 286
SECTION XIII.
Of the incidents, which cause the heat of the extract
to vary from the calculation, the allowances
they require, and the means to obviate
their effects, 289
SECTION XIV.
Of the disposition of the Worts when turned out of
the Copper, the thickness they should be laid at
in the Backs to cool, and the heat they should
retain for fermentation, under the several
circumstances, 304
SECTION XV.
Of Yeast, its nature and contents, and of the manner
and quantities in which it is to be added to
the Worts, 311
SECTION XVI.
Of practical fermentation, and the management of
the several sorts of Malt liquors, to the period
at which they are to be cleansed, or put into
the casks, 318
SECTION XVII.
Of the signs generally directing the processes of
Brewing, and their comparison with the foregoing
Theory and Practice, 327
SECTION XVIII.
An enquiry, into what may be, at all times, a proper
stock of Beer, and the management of it in the
cellars, 331
SECTION XIX.
Of Precipitation, and other remedies, applicable to
the diseases incident to Beers, 334
SECTION XX.
Of Taste, 342
Appendix, 349
THE PREFACE.
_The difference that appears in the several processes of brewing,
though executed with the same materials, by the same persons, and
to the same intent, is generally acknowledged. The uneasiness this
must occasion to those who are charged with the directive part of
the business, cannot be small: and the more desirous they are of
well executing the duty incumbent on them, the greater is their
disappointment, when frustrated in their hopes. To remove this
uncertainty, no method seems preferable to that of experiments, as it
is by this means alone, any art whatever can be established upon a
solid foundation: but these require caution, perseverance, and expence;
they must be multiplied and varied both for the same and for different
purposes. The operations of nature elude superficial enquiries, where
we have few or no principles for our guides, many experiments are
made, which tend only to confound or deceive. Effects seen, without a
sufficient knowledge of their causes, often are neglected, or viewed
in an improper light, seldom faithfully reported, and, for want of
distinguishing the several circumstances that attend them, many times
become the support of old prejudices, or the foundation of new ones._
_Whoever is attentive to the practical part of brewing, will soon be
convinced that heat, or fire, is the principal agent therein, as this
element, used in a greater or less degree, or differently applied, is
the occasion of the greatest part of the variety we perceive. It is but
a few years since the thermometer has been found to be an instrument
sufficiently accurate for any purposes where the measure of heat is
required. And, as it is the only one with which we are enabled to
examine the processes of brewing, and to account for the difference
in the effects, a theory of the art, founded on practice, must be of
later date than the discovery of the instrument that guides us to the
principles._
_So long since as the year 1741, I began this research, and never
neglected any opportunity to consult the artists of the trade, or to
try such experiments as I conceived might be conducive to the purpose.
It is needless, perhaps shameful, to mention their number, or to speak
of the many disappointments I met with in this pursuit. Error admits
of numberless combinations. Truth alone is simple, and confirmed by
continuity. At last, flattering myself with having collected the true
theory, assisted and encouraged by men of abilities, I thought it fit
the public should judge whether I had succeeded in my endeavours; and
in 1758 the Essay on Brewing was submitted to them, either for their
approbation, or that the errors therein might be pointed out. I have
had no reason to repent of my temerity, though perhaps the novelty,
more than the merit of this performance, engaged the attention, I may
add the favor and advice of some good judges. They have allowed my
principles to be at least plausible, and their agreement with practice
has since repeatedly convinced me they were not far from truth._
_The Essay just mentioned, revised and corrected, naturally forms
the first part or theory of the present treatise. The second part is
entirely practical. After giving a short idea of the whole process, I
resume its different branches in as many chapters, and endeavour in
such manner to guide the practitioner, that he may, in every part, at
all times, and under a variety of circumstances, know what he is to do,
and seldom, if ever, to be disappointed in his object._
_From the investigation of so extensive a business, some benefit, it
is hoped, must accrue to the public; from the process of brewing being
carried on in a just and uniform manner, our malt liquors, probably,
will in time better deserve the name of wine._
_Boerhaave, Shaw, Macquer, _and most of the great masters in chymistry
are far from limiting that name to the liquors produced from the juice
of the grape: they extend it to all fermented vegetable juices, which,
on distillation, yield an ardent spirit, and look on the strength
and faculty wine has to cherish nature, and preserve itself, to be
in proportion to the quantity it possesses of this liquid, generally
termed spirit of wine. This, when thoroughly pure and dephlegmated,
is one and the same, whatever different vegetable it is produced
from. Barley wines possess the same spiritous principle, which is the
preservative part of the most valuable foreign wines, with a power of
being brewed superior or inferior to them in quality, and the other
constituent parts of beer, beside this ardent spirit, will not, I
believe, be esteemed less wholesome than those which make up the whole
of grape wine._
_The reasons why Great Britain hath not hitherto furnished foreign
nations with this part of her product, but more especially her seamen,
are obvious. Our mariners, when at home, do not dislike beer, either
as to their palates, or its effects on their constitution; but when
abroad, spiritous liquors, or new wines, often the product of an
enemy’s country, are substituted in lieu thereof. The disuse of beers,
on these occasions, has been owing to the uncertainty of the principles
on which they were brewed; the maintaining them sound in long voyages
and in hot climates, could not sufficiently be depended upon; and
it has been supposed they could not be procured at so easy a rate
as wines, brandies, or rums, purchased abroad. The first of these
objections, the author hopes, by this work, to remove; and, were all
the duties to be allowed on what would be brewed for this purpose, our
seamen might be furnished with beer stronger than Spanish wine, and at
a less expence, the mean price of malt and hops being taken for seven
years. It is true that, in times of peace, the seamen in his Majesty’s
service are not very numerous, but the number of those then employed
by merchants is considerable. I should not have presumed to mention
this, but on account of the encouragement given to the exportation of
corn, and to many manufactures of British growth or British labor. It
is computed that, in England and Wales, are brewed three millions five
hundred thousand quarters of malt yearly, for which purpose upwards of
one hundred and fifty thousand weight of hops are used. The improvement
of the brewery might become a means of increasing the consumption of
the growth of our country, viz. of barley, to more than one hundred
thousand quarters, and of hops to between fourteen and fifteen thousand
weight annually._
_Whether this be an object deserving the attention of the legislative
power, or of the landed interest, and what might be the proper means
to put it successfully in practice, are considerations which do not
belong to this place; it being sufficient here to point out, how
universally beneficial it is to establish the art of brewing on true
and invariable principles._
_This being the first attempt, that has been made, to reduce this
art to rules and principles, the Author hopes he has a just claim
to the indulgence of the public, for any errors he unwillingly may
have adopted; far from believing that there is no room left for
future improvements, he recommends it to those, who, blessed with
superior talents and more leisure than himself, may be inclined
to try their skill in the same field, to watch closely the steps
of_ NATURE; _after the strictest enquiry made, it will be
found, the success of brewing beers and ales wholly depends on a true
imitation of the wines she forms._
_This second edition, it may be observed, in many respects, differs
considerably from the first. I have endeavoured to convert to use every
advice, every opinion I received, and having put these to the test of
farther practice, flatter myself it will be found improved._
A COPY OF DOCTOR SHAW’S LETTER.
ON PERUSING THE ESSAY BEFORE MENTIONED.
DEAR SIR,
_I HAVE, with pleasure and improvement, read over your manuscript; and
should be glad to see some other trades as justly reduced to rules
as you have done that of brewing: which would not only be making
a right application of philosophical knowledge, but, at the same
time, accommodate human life, in many respects, wherein it is still
deficient. Perhaps your example may excite some able men, to give us
their respective trades, in the form of so many arts. For my own part,
having long wished to see some attempts of this kind, for the good
of society in general, I cannot but be particularly pleased with the
nature, design, and execution of your essay, and am,_
_Dear Sir,
Your obliged Friend,
And humble Servant,
PETER SHAW._
Pall-Mall, July 20,
1758.
AN
EXPLANATION
OF THE
TECHNICAL TERMS.
The intent of every brewer, when he forms his drink, is to extract
the fermentable parts of the malt, in the most perfect manner; to add
hops, in such proportion as experience teaches him will preserve and
ameliorate the beer; and to employ just so much yeast as is sufficient
to obtain a complete fermentation.
Perhaps it may be said, these particulars are already sufficiently
understood, and that it would be a much more useful work to publish
remedies for the imperfections, or diseases, beer is naturally or
accidentally subject to, and which at present are deemed incurable. But
if the designs just now mentioned be executed according to the rules
of chymistry, such imperfections and such diseases not existing, the
remedies will not be wanted; for beer brewed upon true principles,
is, neither naturally nor accidentally, subject to many disorders
often perceived in it. Hence it is evident, that some knowledge of
chymistry is absolutely necessary to complete the brewer, as, without
the informations acquired from that science, he must be unqualified to
lay down rules for his practice, and to secure to himself the favor
of the public; for which purpose, and to make this treatise useful to
those concerned in the practical part of brewing, it has been thought
adviseable to avoid, as much as possible, the technical terms of art,
to prefix an explanation of those that necessarily occur, and, in as
short a manner as possible, to trace the properties of fire, air,
water, and earth, as far as they relate to the subject.
ACIDS are all those things which taste sour, as vinegar, juice
of lemons, spirit of nitre, spirit of salt, the oil and spirit of
vitriol, &c. and are put in a violent agitation, by being mixed with
certain earths, or the ashes of vegetables. An acid enters, more or
less, into the composition of all plants, and is produced by, or rather
is the last effect of, fermentation. Mixed in a due proportion with an
alkali, it constitutes a neutral salt, that is, a salt wherein neither
the acid nor alkali prevail. Acids are frequently termed acid salts,
though generally they appear under a fluid form.
ALKALIES, or alkaline salts, are of a nature directly contrary
to the acids, and generally manifest themselves by effervescing
therewith: they have an urinous taste, and are produced from the ashes
of vegetables, and by several other means. They, as well as testaceous
and calcarious substances, are frequently made use of by coopers, to
absorb the acid parts of stale beer, by them called _softning_.
AIR is a thin elastic fluid, surrounding the globe of the earth; it is
absolutely necessary to the preservation both of animal and vegetable
life, and for the exciting and carrying on fermentation.
ALCOHOL is the pure spirit of wine, generally supposed to be without
the least particle of water or phlegm.
ANIMALS are organized bodies, endued with sensation and life. Minerals
are said to grow and increase, plants to grow and live, but animals
only to have sensation.—Animal substances cannot ferment so as to
produce by themselves a vinous liquor; but there may be cases wherein
some of their parts rather help than retard the act of fermentation.[1]
ATMOSPHERE is that vast collection of air, with which the earth is
surrounded to a considerable height.
ATTRACTION is an indefinite term, applicable to all actions whereby
bodies tend towards one another, whether by virtue of their weight,
magnetism, electricity, or any other power. It is not, therefore,
the cause determining some bodies to approach one another, that is
expressed by the word _attraction_, but the effect itself. The space,
through which this power extends, is called the _sphere of attraction_.
BLACKING is a technical term used by coopers, to denote sugar
that is calcined, until it obtains the colour that occasions the name.
BREWING is the operation of preparing beers and ales from malt.
BOILING may thus be accounted for. The minute particles of fuel being
by fire detached from each other, and becoming themselves fire, pass
through the pores of the vessel, and mix with the fluid. These,
being perpetually in an active state, communicate their motion to the
water: hence arises, at first, a small intestine motion, and from a
continued action in the first cause, the effect is increased, and the
motion of the liquor continually accelerated; by degrees, it becomes
sensibly agitated, but the particles of the fire, acting chiefly on
the particles that compose the lowest surface of the water, give them
an impulse upwards, by rendering them specifically lighter, so as
to determine them to ascend, according to the laws of equilibrium.
Hence there is a constant flux of water from the bottom to the top
of the vessel, and reciprocally from the top to the bottom. This
appears to be the reason why water is hot at the top sooner than at
the bottom, and why an equal heat cannot be distributed through the
whole. The thermometer therefore can be of little service, to determine
immediately the degree of heat, especially in large vessels, on which
account it is better for brewers to heat a certain quantity just to
the act of boiling, and to temper it, by adding a sufficient quantity
of cold water. Boiling water is incapable of receiving any increase of
heat, though acted on by ever so great a fire, unless the atmosphere
becomes heavier, or the vapours of the water be confined. It occasions
the mercury to rise, according to Farenheit’s scale, to 212 degrees.
CHARR. A body is said to be charred when, by fire, its volatile or most
active parts are drove out; its coarse oils, by the same means, placed
chiefly on the external parts; and so deprived of color as to be quite
black.
CLEANSING is the act of removing the beer from the ton, where
it was first fermented, into the casks.
CLOUDY is an epithet joined to such beers, which, from the
violent heat given to the water that brewed them, are loaded with more
oils than can be attenuated by fermentation, and incorporated with
the water; from whence a muddy and grey oil is seen floating on the
surface of the liquor, though the body is often transparent; this oil
is frequently extracted in such quantity as to exceed the power of any
known menstruum.
COHESION is that action by which the particles of the same body adhere
together, as if they were but one.
COLD is a relative term in opposition to heat. Its greatest degree is
not known, and it is supposed that the colder a body is, the less is
the agitation of its internal parts.
COLOUR; a greater or less degree of heat causes different colours in
most bodies, and from a due observation of the colour of malt, we may
determine what degree of heat it has been impressed with.
DENSITY expresses the closeness, compactness, or near approach of the
parts of a body to one another: the more a body weighs in proportion
to its bulk, the greater is its density. Gold is the densest body in
nature, because there is none known of the same bulk, which weighs so
much.
EARTH is that fossil matter or element, whereof our globe partly
consists.
EBULLITION is the boiling or bubbling of water, or any other liquor,
when the fire has forced itself a passage through it. Brewers suppose
water to be just beginning to boil, when they perceive a small portion
of it forced from the bottom upwards in a right line, so as to disturb
the surface: when the liquor is in this state, they call it _through_,
or upon the point of ebullition. The vulgar notion that the water is
hotter at this time than when it boils, is without any foundation.
EFFERVESCENCE is a sudden agitation, arising in certain bodies upon
mixing them together; this agitation most commonly generates heat.
ELASTICITY, or springiness, is that property of bodies, by which they
restore themselves to their former figure, after any pressure or
distension.
EXPANSION is the swelling or increase of the bulk of bodies from heat,
or any other cause.
EXTRACT consists of the parts of a body separated from the rest, by
cold or hot water.
FERMENTATION is a sensible internal motion of the particles of
a mixture: by the continuance of this motion, the particles are
gradually removed from their former situation, and, after some visible
separation, joined together again in a different order and arrangement,
so as to constitute a new compound. No liquors are capable of
inebriating, except those that have been fermented.
FIXED BODIES are those, which, consisting of grosser parts, cohering by
a strong attraction, and by that means less susceptible of agitation,
can neither be separated nor raised, without a strong heat, or perhaps
not without fermentation.
FIRE is only known by its properties, of which the chief are to
penetrate and dilate all solid and fluid bodies.
FREEZING POINT is the degree of cold, at which water begins to be
formed into ice, which, according to Farenheit’s scale, is expressed by
32.
FOXED is a technical term, used by brewers, to indicate beers in a
putrid state.
GUMS are concreted vegetable juices, which transude through the bark
of certain trees, and harden upon the surface; they easily dissolve in
water, and by that means distinguish themselves from balsams or resins.
HERMETICALLY SEALED is a particular method of stopping the mouth of
vessels, so close that the most subtil spirit cannot fly out, which is
done by heating the neck of the bottles, till it is just ready to melt,
and then with hot pinchers twisting it close together.
HOMOGENEOUS is an appellation given to such parts or subjects, which
are similar or of the same nature and properties.
ISINGLASS is a preparation from a fish called huso, somewhat bigger
than the sturgeon; a solution of which in stale beer is used, to fine
or precipitate other beers: it is imported from Russia by the Dutch,
and from them to us.
LIGHT consists of particles of matter inconceivably small, capable of
exciting in us the sensation of colours, by being reflected from every
point of the surface of luminous bodies; but, notwithstanding they are
so exceeding small, Sir Isaac Newton found means to divide a single
ray into seven distinct parts, viz. red, orange, yellow, green, blue,
indigo, and violet.
MALT, in general, is any sort of grain, first germinated, and then
dried, so as to prevent any future vegetation: that generally used, is
made of barley, which experience has found to be the fittest for the
purpose of brewing.
MEDIUM is that space, through which a body in motion passes: air is
the medium through which the bodies near the earth move; water is the
medium wherein fish live; glass affords a medium or a free passage
to light.—This term is also made use of, to express the mean of two
numbers, and sometimes the middle between several quantities.
MUSTS are the unfermented juices of grapes, or of any other vegetable
substances.
MENSTRUUM is any fluid, which is capable of interposing its parts
between those of other bodies, and in this manner either dissolves them
perfectly, or extracts some part of them.
OIL is an unctuous, inflammable substance, drawn from several animal
and vegetable substances.
PRECIPITATION. Isinglass dissolved becomes a glutinous and heavy body;
this put into malt liquors intended to be fined, carries down, by its
weight, all those swimming particles, which prevent its transparency;
and this act is called fining, or precipitation.
REPULSION; “Doctor Knight defines it to be that cause which makes
bodies mutually endeavour to recede from each other, with different
forces at different times.” In this case they are placed beyond the
sphere of each other’s attraction or cohesion, and mutually fly from
each other.
RESINS, or balsams, are the oils of vegetables inspissated and combined
with a proportion of the acid salts; as well as they mix with any
spirituous liquor, as little are they soluble in water; but they become
so, either by the intervention of gums or soaps, or by the attenuating
virtue of fermentation.
SALTS are substances sharp and pungent, which readily dissolve in
water, and from thence, by evaporation, crystallise and appear in a
solid form. They easily unite together, and form different compounds.
Thus salts, composed of acids and alkalies, partake of both, and are
called neutral.
SETT: a grist of malt is by brewers said to be sett, when, instead
of separating for extraction, it runs in clods, increases in heat,
and coagulates. This accident is owing to the over quantity of fire
in the water, applied to any of the extractions. The air included in
the grist, which is a principal agent in resolving the malt, being
thereby expelled, the mass remains inert, and its parts, adhering too
closely together, are with difficulty separated. Though an immediate
application of more cold water to the grist is the only remedy, yet, as
the cohesion is speedy and strong, it seldom takes effect.—New malts,
which have not yet lost the heat they received from the kiln, are most
apt to lead the brewer into this error, and generally in the first part
of the process.
SUGAR, or saccharine salts, are properly those that come from the sugar
canes; many plants, fruits and grains give sweet juices reducible
to the same form; they are supposed to be acids smoothed over with
oils; all vegetable sweets are capable of fermenting spontaneously
when crude; if boiled, they require an addition of yeast to make them
perform that act. Malt, or its extracts, have all the properties of
saccharine salts.
SULPHUR. Though by sulphur is commonly understood the mineral
substance called brimstone, yet in chymistry it is frequently used
to signify in general any oily substance, inflammable by fire, and,
without some saline addition, indissoluble in water.
SOAP OR SAPONACEOUS JUICES. Common soap is made of oil mixed with
alkaline salts: this mixture causes a froth on being agitated in water.
The oils of vegetables are, in some degree, mixed with their salts;
and according to the nature of these salts, appear either resinous
or saponaceous, that is, soluble or indissoluble in water.— Sugar
is a kind of soap, rendering oil miscible with water; and therefore
all bodies, from which saccharine salts are extracted, may be termed
saponaceous.
VEGETABLE is a term applied to plants, considered as capable of growth,
having vessels and parts for this purpose, but generally supposed to be
without sensation.
VINEGAR is an acid penetrating liquor, prepared from wine, beer, cyder,
or a must, which has been fermented as far as it was capable.
VITRIOL is, in general, a metalline substance combined with the
strongest acid salt known. This acid, being separated from the metal,
differs in nothing from that which is extracted from alum or brimstone.
It is improperly called spirit of vitriol, when diluted with water,
and, with as little propriety, oil, when free from it.
VOLATILE BODIES are those, which, either from their smallness or
their form, do not cohere very strongly together, and being most
susceptible of those agitations, which keep liquors in a fluid state,
are most easily separated and rarified into vapour, with a gentle heat,
and on the contrary condensed and brought down with cold.
WINE is a brisk, agreeable, spirituous, fluid cordial, formed from
fermented vegetable bodies. In this sense beers and ales may be called,
and really are, barley wines.
WORTS are the unfermented extracts of malt.
YEAST is both the flowers and lees of a fermented wort, the former of
these being elastic air enveloped in a subject less strong and less
consistent than the latter.
_PRINCIPLES OF THE THEORY OF BREWING._
SECTION I.
_OF FIRE._
Though fire is the chief cause and principle of almost every change
in bodies, and though persons untaught in chymistry imagine they
understand its nature, yet, certain it is, few subjects are so
incomprehensible, or elude so much our nicest research. The senses are
very inadequate judges of it; the eye may be deceived, and suppose no
fire in a bar of iron, because it does not appear red, though at the
same time it may contain enough to generate pain: the touch is equally
unfaithful, for a body, containing numberless particles of heat, will
to us feel cold, if it is much more so than ourselves.
The great and fundamental difference among philosophers, in respect
to the nature of fire, is, whether it be originally such, formed by
the Creator himself, at the beginning of things; or whether it be
mechanically producible in bodies, by inducing some alteration in the
particles thereof. It is certain that heat may be generated in a body,
by attrition; but whether it existed there before, or was caused
immediately by the motion, is a matter of no great import to the art of
brewing; for the effects, with which we are alone concerned, are the
same.
Fire expands all bodies, both solid and fluid. If an iron rod just
capable of passing through a ring of the same metal, is heated red-hot,
it will be increased in length, and so much swelled as not to be
able to pass through the ring, as before:[2] if a fluid is put into
a bellied glass, with a long slender neck, and properly marked, the
fluid, by being heated, will manifestly rise to a considerable height.
The expansion of fluids, by heat, is different in different fluids;
with some exceptions, it may be said to be in proportion to their
density. Pure rain water, gradually heated to ebullition, is expanded
one 26th part of its bulk,[3] so that 27 gallons of boiling water,
will, when cold, measure no more than 26, and 27 gallons of boiling
wort will not yield so much, because worts contain many oily particles,
which, though less dense than water, have the property of being more
expansible: hence we see the reason why a copper, containing a given
number of barrels of wort, when cold, is not capable to hold the same
of beer, when boiling.
Bodies are weakened or loosened in their texture by fire: the hardest,
by an increased degree of heat, will liquify and run; and vegetables
are resolved and separated by it into their constituent parts. It must
be owned vegetables seem at first, on being exposed to the fire, to
become rigid or stiff; but this is owing to the evaporation of the
aqueous particles, which prevented a closer adhesion of the solid
matter. It is only in this manner fire strengthens some bodies which
before were weak.
That the texture of bodies should be loosened by fire, seems a
consequence of expansion; for a body cannot be expanded but by its
particles receding farther from one another; and if these be not able
to regain the situation they had when cold, the body will remain looser
in its texture than before it suffered the action of fire. This is the
case of barley when malted.
Fire may be conveyed through most bodies, as air, water, ashes, sand,
&c. The effect seems to be different according to the different
conveyances. A difference appears between boiling and roasting, yet
they answer the same purpose, that of preserving the subject; and
this, in proportion to the degree of heat it has suffered. A similar
variety appears, even to our taste, from the different conveyance of
fire to malt: for acids having a great tendency to unite with water,
if this element does not naturally contain any itself, is the reason
why a great heat is conveyed through water, and applied to extract the
virtues of pale malt; the water gaining from the grain some of these
salts, or possessing them itself, the effect of this great aqueous heat
is not to imprint on the palate a nauseous burnt taste, as is the case
of great heats, when conveyed through air to the same grain. The salts
the water has obtained, or perhaps had, being sheathed by the oils it
draws from the malt, rather become saccharine, which cannot be the case
when oils are acted upon by a strong heat, entirely void of any such
property; but malt, the more it is dried, the longer is it capable of
maintaining itself in a sound state, and the liquor brewed with it
will, in proportion to its dryness, keep the longer sound, the hotter
the water is, applied to malt, provided its heat doth not exceed the
highest extracted degree, the more durable and sound will the extract
be.
The last consideration of fire or heat, relative to brewing, is the
knowledge of its different degrees, and how to regulate them. Till
of late, chymists and all others, were much to seek in this respect;
they distinguished more or less fire in a very vague and indeterminate
manner, as the first, second, third, and fourth degree of heat,
meaning no precise heat, or heat measured by any standard; but, by
the invention of the thermometer, we are enabled to regulate our
fires with the utmost precision. Thermometers are formed on different
scales; and therefore, when any degree of heat is mentioned, in order
to avoid confusion, the scale made use of should be indicated. I have
constantly employed Fahrenheit’s, as it is the most perfect, and the
most generally received. According to this instrument,[4] by the author
of it, an artificial cold was made so as the mercury stood at 72
divisions below the first frost. The gentlemen of the French Academy,
in the winter of the year 1736, observed, at Torneao, Latitude 65°
51´, the natural cold to be 33 degrees below 0: these are proofs there
are colds much more intense than the first frost, or 32 degrees, where
water first begins to harden into ice; from 32 to 90 degrees are the
limits of vegetation, according to the different plants that receive
those or the intermediate heats. The 40th degree is marked by Boerhaave
as the first fermentable heat, and the 80th as the last: 47 degrees I
have found to be generally the medium heat of London, throughout the
year, in the shade; 98 degrees is said to be that of our bodies when
in health, as from 105 to 112 are its degrees when in a fever. Hay
stacked with too much moisture, when turned quite black, in the heart
of the rick, indicated a heat of 165 degrees. At 175 the purest and
highest-rectified spirits of wine boil, and at this degree I have
found well-grown malts to charr, at 212 degrees water boils, at 600
quicksilver and oil of vitriol. Gold, silver, iron, and most other
metals in fusion exceed this heat; greater still than any known is
the fire in the focus of the burning lens of Tschirnhausen, or of the
concave mirror made by Villette; they are said to volatilise metals and
vitrify bricks. Thus far experiments have reached; but how much more,
or how much less, the power of this element extends, will probably be
forever hid from mankind.
SECTION II.
_OF AIR._
None of the operations, either of nature or art, can be carried on
without the action or assistance of air. It is a principal agent in
fermentation; and therefore brewers ought to be well acquainted with
its principal properties and powers.
By air we mean a fluid, scarcely perceptible to our senses, and
discovering itself only by the resistance it makes to bodies. We find
it every where incumbent on the surface of the globe, rising to a
considerable height, and commonly known by the name of atmosphere. The
weight of air is to that of water as 1 to 850, and its gravitating
force equal to that of a column of water of 33 feet high; so that an
area of one foot square receives, from air, a pressure equal to 2080
pounds weight.
Elasticity is a property belonging only to this element, and this
quality varies in proportion to the compressing weights. We scarcely
find this element, (any more than the others) in a pure state; one
thousandth part of common air, says Boerhaave, consists of aqueous,
spiritous, oily, saline, and other particles scattered through
it.—These are not, or but little, compressible, and in general prevent
fermentation: consequently, where the air is purest, fermentation is
best carried on. The same author suspects, that the ultimate particles
of air cohere together, so as not easily to insinuate themselves into
the smallest pores, either of solids or fluids. Hence, those acquainted
with brewing, easily account, why very hot water, which forces strong
and pinguious particles from malt, forms at the same time extracts
unfavourable for fermentation, as oils are an obstruction to the free
entrance of air; and, from an analogous reason, extracts which are much
less impressed with fire, in them fermentation is so much accelerated,
that the whole soon becomes sour.
Air, like other bodies, is expanded and rarified by heat, and exerts
its elasticity in proportion to the number of degrees of fire it has
received; the hotter therefore the season is, the more active and
violent will the fermentation be.
Air abounds with water, and is perpetually penetrating and insinuating
itself into every thing capable of receiving it. Its weight, or
gravitating force, must necessarily produce numberless effects. The
water contained in the air is rendered more active by its motion;
hence the saline, gummous, and saponaceous particles it meets with
are loosened in their texture, and, in some degree, dissolved. As
principles similar to these are the chief constituent parts of malt,
the reason is obvious why such, which are old, or have lain a proper
time exposed to the influence of the air, dissolve more readily, or,
in other words, yield a more copious extract than others.
All bodies in a passive state, remaining a sufficient time in the same
place, become of the same degree of heat with the air itself. On this
account the water, lying in the backs used by brewers, is nearly of
the same degree of heat as the thermometer shews the open air in the
shade to be. When this instrument indicates a cold below the freezing
point, or 32 degrees, if the water does not then become ice, the reason
is, because it has not been exposed long enough to be thoroughly
affected by such a cold. For water does not immediately assume the
same degree of temperature with the air, principally on account of its
density, also from its being pumped out of deep and hot wells, from
its being kept in motion, and from many other incidents. Under these
circumstances, no great error can arise to estimate its heat equal to
35 degrees.
Air is not easily expelled from bodies, either solid or fluid. Water
requires two hours boiling to be discharged of the greatest part of its
air. That it may be thus expelled by heat appears from hence; water, if
boiled the space abovementioned, instead of having any air bubbles when
it is froze, as ice commonly has, becomes a solid mass like crystal.
Worts or musts, as they contain great quantities of salts and oils,
require a greater degree of heat to make them boil: consequently more
air is expelled from boiling worts, than from boiling water in the same
time; and as air doth not instantaneously re-enter those bodies,[5]
when cold, they would never ferment of themselves. Were it not for the
substitute of yeast, to supply the deficiency of air lost by boiling,
they would fox or putrify, for want of that internal elastic air, which
is absolutely necessary to fermentation.
As air joined to water contributes so powerfully to render that fluid
more active, that water which has endured fire the least time, provided
it be hot enough, will make the strongest extracts.
Though there is air in every fluid, it differs in quantity in different
fluids; so that no rule can be laid down for the quantity of air, which
worts should contain.—Probably the quantity, sufficient to saturate one
sort, will not be an adequate proportion for another.
Air in this manner encompasses, is in contact with, confines, and
compresses all bodies. It insinuates itself into their penetrable
passages, exerts all its power either on solids, or fluids, and finding
in bodies some elements to which it has a tendency, unites with them.
By its weight and perpetual motion, it strongly agitates those parts
of the bodies in which it is contained, rubs, and intermixes them
intimately together. By disuniting some, and joining others, it
produces very singular effects, not easily accomplished by any other
means.—That this element has such surprising powers, is evident from
the following experiment. “Fermentable parts duly prepared and disposed
in the vacuum of Mr. Boyle’s air-pump will not ferment, though acted
upon by a proper heat; but, discharging their air, remain unchanged.”
SECTION III.
_OF WATER._
As water is perpetually an object of our senses, and made use of for
most of the purposes of life, it might be imagined the nature of this
element was perfectly understood: but they who have enquired into it
with the greatest care, find it very difficult to form a just idea of
it. One reason of this difficulty is, water is not easily separated
from other bodies, or other bodies from water. Hartshorn, after having
been long dried, resists a file more than iron; yet, on distillation,
yields much water. I have already observed, that air is intimately
mixed with, and possibly never entirely separated from it, but in a
_vacuum_; how is it possible then ever to obtain water perfectly pure?
In its most perfect state, we understand it to be a liquor very fluid,
inodorous, insipid, pellucid, and colourless, which, in a certain
degree of cold, freezes into a brittle, hard, glassy ice.
Lightness is reckoned a perfection in water, that which weighs less
being in general the purest. Hence the great difficulty of determining
the standard weight it should have. Fountain, river, or well waters,
by their admixture with saline, earthy, sulphureous, and vitriolic
substances, are rendered much heavier than in their natural state; on
the other hand, an increase of heat, or an addition of air, by varying
the expansion, diminishes the weight of water. A pint of rain-water,
supposed to be the purest, is said to weigh 15 ounces, 1 drachm, and 50
grains, but, for the reasons just now mentioned, this must differ in
proportion as the seasons of the year do from each other.
Another property of water, which it has in common with other liquors,
is its fluidity, which is so great, that a very small degree of heat,
above the freezing point, makes it evaporate. Experiments to ascertain
the proportion steamed away of the quantity of water used in brewing,
is an object worthy of the artist’s curiosity; but the purer the water
is, the more readily it evaporates. Sea-water, which is supposed to
contain one fortieth part of salt, more forcibly resists the power of
fire, and wastes much less, than that which is pure.
The ultimate particles of this element, Boerhaave believed to be
much less than those of air, as water passes through the pores and
interstices of wood, which never transmit the least elastic air; nor is
there, says he, any known fluid, (fire excepted, which forces itself
through every subject) whose parts are more penetrating than those of
water. Yet as water is not an universal dissolver, there are vessels
which will contain it, though they will let pass even the thick syrup
of sugar, for sugar makes its way by dissolving the tenacious and oily
substance of the wood, which water cannot do.
Water, when fully saturated by fire, is said to boil, and by the
impulse of that element, comes under a strong ebullition. Just before
this violent agitation takes place, I have already observed, it
occupies one seventy-sixth more space than when cold: so the brewer
who would be exact, when he intends to reduce his liquor to a certain
degree of heat, must allow for this expansion, abating therefrom the
quantity of steam exhaled.
As water, by boiling, may be said to be filled or saturated with fire,
so may it be with any other substance capable of being dissolved
therein; but, though it will dissolve only a given quantity of any
particular substance, it may, at the same time, take in a certain
proportion of some other. Four ounces of pure rain water will melt
but one ounce of common salt, and after taking this as the utmost of
its quantity, it will still receive two scruples of another kind of
salt, viz. nitre. In like manner the strongest extract of malt is
capable of receiving the properties belonging to hops: but in a limited
proportion. This appears from the thin bitter pelicle, that often
swims on the surface of the first wort of brown beers, which commonly
are overcharged with hops, by putting the whole quantity of them at
first therein; the wort not being capable of suspending all that the
heat dissolves, it no sooner cools but these parts rise on the top.
This may serve as a hint to prevent this error, by suffering the first
wort to have no more hops boiled therein than it can sustain: but as
this incident must vary, in proportion to the heat of the extracts and
quantity of water used, some few experiments are necessary to indicate
the due proportion for the several sorts of drink. This however should
always be extended to the utmost, for the first wort, which, from its
nature and constituent parts, stands most in need of the preservative
quality the hops impart.
Water acts very differently, as a menstruum, according to the quantity
of fire it contains: consequently its heat is a point of the utmost
importance with regard to brewing, and should be properly varied
according to the dryness and nature of the malt, according as it is
applied either in the first or last mashes, and in proportion also to
the time the beer is intended to be kept. These ends, we hope to shew,
are to be obtained to a degree of numerical certitude.
Nutrition cannot be carried on without water, though likely water
itself is not the matter of nourishment, but only the vehicle.
Water is as necessary to fermentation as heat or air. The farmer,
who stacks his hay or corn before it is sufficiently dried, soon
experiences the terrible effects of too much moisture, or water,
residing therein: all vegetables therefore intended to be long kept,
ought to be well dried. The brewer should carefully avoid purchasing
hops that are slack bagged, or kept in a moist place, or malt that has
been sprinkled with water soon after it was taken from the kiln. By
means of the moisture, an internal agitation is raised in the corn,
which agitation, though soon stopped, for want of a sufficient quantity
of air, yet, the heat thereby generated remaining, every adventitious
seed, fallen from the air, and resting on the corn, begins to grow,
and forms a moss, which dies, and leaves a putrid musty taste behind,
always prevailing, more or less, in beer made from such grain.
That water is by no means an universal solvent, as some people have
believed, has been already observed. It certainly does not act as such
on metals, gems, stones, and many other substances: it is not in itself
capable of dissolving oils, but is miscible with highly rectified
spirits of wine, or alchohol, which is the purest vegetable oil in
nature. All saponaceous bodies, whether artificial or natural, fixed
or volatile, readily melt therein; and as many parts of the malt are
dissoluble in it, they must either be, or become by heat, of the nature
of soap, that is, equally miscible with oils and water.
When a saponaceous substance is dissolved in water, it lathers,
froths, and bears a head; hence, in extracts of malt, we find these
signs in the underback. Weak and slack liquors, which contain the
salts of the malt without a sufficient quantity of the oils, yield no
froth. Somewhat like this happens, when the water for the extract is
over-heated, for then as more oils are extracted than are sufficient to
balance the salts, the extract comes down as before, with little or no
froth or head. This sameness of appearance, from two causes directly
opposite to each other, has many times misled the artist, and shews the
necessity there is to employ means less liable to error.
This might be a proper place to observe the difference between rain,
spring, river, and pond waters; but as the art of brewing is very
little affected by the difference of waters, if they be equally soft,
but rather depends on the due regulation of heat; and as soft waters
are found in most places, and become more alike, when heated to the
degree necessary to form extracts from malt; it is evident, that any
sort of beer or ale may be brewed with equal success, where malt and
hops can be procured proper for the respective purposes. If hitherto
prejudice and interest have appropriated to some places a reputation
for particular sort of drinks, it has arose from hence; the principles
of the art being totally unknown, the event depended on experience
only, and lucky combinations were more frequent where the greatest
practice was. Thus, for want of knowing the true reason of the
different properties observed in the several drinks, the cause of their
excellencies or defects was ignorantly attributed to the water made use
of, and the inhabitants of particular places soon found an advantage,
in availing themselves of this local reputation. But just and true
principles, followed by as just a practice, must render the art more
universal, and add dignity to the profession, by establishing the merit
of our barley wines on knowledge, not on opinion void of judgment. To
place this truth in a fuller light, and to communicate to the brewer
the readiest means to examine any waters he may have occasion to use,
I have extracted from Doctor Lucas’s Essay on Waters, the experiments
he made on the Thames, New River, and Hampstead company’s waters, but
without closely adhering to the accuracy this gentleman prescribed to
himself; such exactness much better suiting a man of his abilities: for
the purposes of brewing it is not of absolute necessity.
_Experiments on the Thames, New River, and Hampstead Waters, which in
general are in use in the Cities of London and Westminster.
_Subjects |_Thames, at |_Inferences |_New River._ |_Hampstead._
employed._ | Somerset | from the | |
| House._ | experiments | |
| | on Thames | |
| | water._ | |
| | | |
|Quantity of | |Quantity of |In 24 hours
|insoluble | |insoluble |discharges air,
|matter in one | |matter in one |lets some light
|pint, one | |pint, one |sediment fall,
|grain and a | |grain and a |and grows
|half. | |half. |clearer.
---------- | ---------- | ---------- | ---------- | ----------
|Quantity of | |Quantity of |Quantity of
|water used | |water used |water used
|two ounces. | |two ounces. |two ounces.
| | | |
Twenty drops |Produced--a |A small |Produced a |Produced, 1st
syrup of |sea-green. |quantity of |paler green. |a sea-green;
violets. | |alkaline | |upon standing,
| |principle. | |heightens; in
| | | |12 hours
| | | |becomes
| | | |yellowish.
---------- | ---------- | ---------- | ---------- | ----------
Infusion of |A pink color |A calcarious |A paler pink; |A pink bloom;
campechy wood |heighten to |earth dis- |but heightens |upon standing
to a dark |crimson. |solved in a |as Thames. |heightens; after
orange. | |marine acid, | |fades, and
| |perhaps | |comesto the
| |something of a| |color of old
| |volatil | |Canary Wine.
| |alkaly, whence| |
| |the water | |
| |appears unfit | |
| |for the | |
| |scarlet dye. | |
---------- | ---------- | ---------- | ---------- | ----------
1 grain of |A pink bloom |Confirms the |The same as |A very beautiful
cochinelle, |heightens to |preceding |the Thames |crimson;
in powder. |crimson; fades|experiment. |water. |heightens upon
|to a pale | | |standing; in 12
|muddy purple, | | |hours suffers
|letting fall | | |no diminution
|obscure green | | |of color.
|clouds. | | |
---------- | ---------- | ---------- | ---------- | ----------
Alcaline lye, |Slight milky |Charged with |Less milky, |Of alkaline lye
5 drops. |cloud; becomes|terrine parts,|with less |used ten drops.
|milky all |dissolved by |sediment. |--Worked no
|over; a light |means of an | |sensible change
|sediment of |acid; at high | |in this water.
|pale earth |water more | |
|coats the |acid in the | |
|glass, and is |water than at | |
|found at |low, and the | |
|bottom. |alkaline | |
| |principle in | |
| |this river | |
| |more at low | |
| |water than | |
| |at high. | |
---------- | ---------- | ---------- | ---------- | ----------
Solution of |A pearl- |Confirms the |Less milky; no|Mixes smoothly,
Soap. |colored |former |coagulation. |and causes a
|milkiness, |observation. | |slight
|but no | | |lactescence.
|coagulation. | | |
---------- | ---------- | ---------- | ---------- | ----------
A diluted acid|No perceptible|Shews an |No sensible |Upon standing
of vitriol. |change. |alkaly not |change. |shews some air
| |predominant. | |bubbles, and
| | | |seems somewhat
| | | |brighter.
---------- | ---------- | ---------- | ---------- | ----------
Mercury |No change; |The quantity |The same |The same
sublimate |upon standing,|of alkaly in- |appearance as |appearance, but
dissolved in |a mother of |considerable. |Thames; rather|rather slighter
pure water, |pearl colored | |slighter |than any of the
10 drops. |pellicle | |precipitation.|other two.
|covered the | | |
|surface; the | | |
|liquor beneath| | |
|slightly | | |
|milky. | | |
---------- | ---------- | ---------- | ---------- | ----------
A solution of |Pale clouds at|Shews some |The same as |Upon dropping,
mercury in the|every drop; |absorbent |Thames, but |no change
acid of nitre.|1st white and |earth, by |slighter. |appears; upon
|milky, then |means of an | |standing grows
|yellowish |acid, | |milky, then to
|four drops |suspended in | |a pale yellow,
|more got the |the water. | |with a slight
|same color | | |pearl-colored
|all over; upon| | |pellicle; shews
|standing, a | | |no air nor
|slight pale | | |sediment; the
|pellicle | | |glass slightly
|arose, and a | | |coated upon
|muddy ochre- | | |standing;
|colored | | |precipitated
|sediment | | |fairly.
|subsided. | | |
---------- | ---------- | ---------- | ---------- | ----------
A solution of |A bright milky|Confirms the |The same as |The same as
lead in |cloud, which, |preceding |Thames, but in|New River.
distilled |growing more |observation. |a lower |
vinegar, at |opac and | |degree. |
every drop as |white, | | |
far as 4 |subsided; upon| | |
drops. |being stirred,| | |
|had a milky | | |
|opacity all | | |
|over; upon | | |
|standing, | | |
|threw up a | | |
|pale pellicle,| | |
|and let fall | | |
|white | | |
|precipitate. | | |
---------- | ---------- | ---------- | ---------- | ----------
A solution of |Caused a |Shews some |The same |Pale bluish
silver in the |pearled |portion of |effects, but |white clouds;
acid of nitre,|milkiness; |sea-salt, of |slighter; the |the
4 drops. |upon standing |which the |precipitate of|precipitate,
|subsided a |Thames has |a pale violet |a bluish slate
|violet purple |more at high |color. |color, thinly
|colored |water than at | |covered the
|precipitate. |low. | |sides and
| | | |bottom of the
| | | |glass.
All these waters appear to be sufficiently pure for the common uses of
life; the difference between them is very trivial, if any: those of
Hampstead approach nearest to the simple state this element is to be
wished for. Although it cannot be said to have an immediate relation to
this work, yet it may not, perhaps, be disagreeable or useless here to
add the quantities of water the cities of London and Westminster, and
the adjacent buildings, are daily supplied with.
From the New River Company 57897 Tons per Day.
London Bridge, 8500
Chelsea, 1740
Hampstead, 1200
York Buildings, 849
Hartshorn Lane, 205
------
70391 Tons required
every 24 hours.
SECTION IV.
_OF EARTH._
Regularity requires some notice should be taken of this element.
The great writer on chymistry, so often mentioned, defines it to be
a simple, hard, friable, fossil body, fixed in the fire, but not
melting in it, nor dissoluble in water, air, alcohol, or oil. These
are the characters of pure earth, which, no more than any of the other
elements, comes within our reach, free from admixture. Though it is
one of the component parts of all vegetables, yet as, designedly, it
is never made use of in brewing, except sometimes for the purpose of
precipitation; it is unnecessary to say any thing more upon it: whoever
desires to be farther informed concerning its properties may consult
all, or any of the authors before mentioned.
SECTION V.
_OF MENSTRUUMS OR DISSOLVENTS._
By menstruums is understood a body which, in a fluid or subtilised
state, is capable of interposing its small parts betwixt the small
parts of other bodies. This act so obviously relates to the art of
brewing, especially where the extracting of the malt and the boiling of
the hops are concerned, that it should not be passed unheeded by.
The doctrine of menstruums, as laid down by Boerhaave, seems most
intelligible and applicable to our purpose. He says, the solutions of
bodies in general are the effect only of attraction and repulsion,
between the particles of the menstruums and those of the body
dissolved, the whole action depending on the relation between these
two; of consequence, there cannot be any body, natural or artificial,
which, without distinction, will dissolve all bodies whatsoever; nor is
the cause assignable why certain menstruums dissolve certain bodies:
the effects of alcaline, acid, neutral, fixed, or volatile salts, any
more than those of oils, water, alcohol, fire, or air, are not to
be accounted for by any general rule, that universally holds true;
nor even, in many cases, doth the dissolution of a body depend on
the purity or simplicity of the menstruum: the nearest path then to
success, is cautiously to apply every menstruum we know of to the body
whose solvent we want to discover.
The elements of fire and air greatly promote the action and effect
of menstruums, and in this light they are admitted as such. Water
dissolves most salts, all the natural sapos of plants, and the ripe
juices of fruits; for in these, the oils, salts, and spirit of the
vegetables, are accurately mixed and concreted together, and malts,
having the same constituent parts with them, this element becomes a
proper menstruum to extract this grain: though malts, by being dried
with heats which greatly exceed what is necessary to bring barley to a
state of maturity, do, from hence, require greater, though determinate
heats, yet inferior to that at which water boils; but such heats
must be applied in proportion to their dryness, to extract their
necessary parts. Even earths, by the intervention of acids, dissolve
in water; but having treated of the four elements already, as far as
we conceived was requisite for the art of brewing, we shall, in this
chapter, confine ourselves to oils and salts, and view these acting as
menstruums only.
To the definition already given of oils, it may be necessary to add,
in general, they contain some water, and a volatile acid salt; that
they receive different appellations, and have different properties
in proportion to their respective spissitudes. Oils from vegetables
are obtained by expression, infusion, and distillation; in either of
which methods, a too great heat is to be avoided, as this gives them
a prejudicial rancidness, and where water does not interpose, alters
their color until thereby they are turned black.
In general oils unite with themselves, but, excepting alcohol, not with
water, unless when combined with salts, for salts attract water, and so
they do oils: hence arises many elegant preparations both natural and
artificial, from which wines are formed.
The power of oils in dissolving bodies is in a proportion to their
heat, and being capable, when pure, of receiving a quantity of fire
equal to 600 degrees, it is not surprising this liquid should mix with
gums and with resinous bodies; but the color of these, and of every
subject when thrown into boiling oils, changes in proportion to the
impression made on them by heat, either to a yellow, a red, or a black.
Oils which are inspissated, or thickened by heat, are termed balsams.
Do not the oils of malt, from the heat they have undergone, resemble
these? and from the circumstance of their having endured a heat
superior to that necessary for putrefaction, may they not be suspected
to possess a volatile alcaline salt? Beyond doubt, the extracts from
malt (though they boil at a heat of 218 degrees only) yet do they, in
great measure, dissolve hops, which are gum resinous.
Salt may well be denominated a menstruum, as it is easily diluted
with water; fixed alcaline salts we have already seen appear to be the
produce of fire alone.—Such are never distinguished in the composition
of vegetables in their natural state; though a volatile alcalious
salt (the effect of heat equal or superior to that necessary for
putrefaction) is found in many, and especially in such as are putrified.
The power of a fixed alcali as a solvent is great, applied (says
Boerhaave) to animal, vegetable, or fossil concretions, so far as they
are oils, balsams, gummy, resinous, or of gummy resinous nature, and
therefore concreted from oily substances: these, this salt intimately
opens, attenuates, and resolves: disposing them to be perfectly
miscible with water: oils of alcohol leaving however the impression of
taste naturally belonging to this salt.
Vegetable acid salt dissolves animal, vegetable, fossil, and metalline
substances, except mercury, silver, and gold. In most terrestrial
vegetables this salt is evident; ripe mealy corn has the least
indication of it, yet extracts therefrom, when fermented, and sometimes
before they are fermented, discover sensibly their acidity. Sea-plants
in general have not their roots inserted in the earth at the bottom
of the sea, and these in distillation yield an oily volatile alcali;
but more subtil than the native acids of vegetables, are the vinous
acids produced by fermentation; they dissolve equally most matters
put into them, and render the whole homogene. Into a must or wort,
when under this act, by means of an elæosaccharum, might be introduced
the choicest flavors, and the aromatics of the Indies be applied to
heighten the taste and flavor of our barley wines. The laws of England
at present subsisting are indeed opposite to any improvement of this
sort, from the apprehensions of abuse: but where elegance alone is
intended, undoubtedly the merit of our beers and ales might thereby be
increased. As such, this is a part of chymical knowledge well worth the
enquiry and attention of the brewer.
Neutral salts have already been mentioned; these are very various,
and very different when acting as menstruums. Resins and gum-resins
are generally said to be most effectually dissolved by alcohol; but
Boerhaave informs us, that sal-amoniac (a very salutary subject and
a neutral salt) if boiled with gums, resins, or the gum-resins of
vegetables, intimately resolves, and disposes them to be conveniently
mixed in aqueous and fermenting spiritous menstruums. Of this class of
salts thus much is sufficient. This observation perhaps is of too much
consequence to escape the notice of the artist.
SECTION VI.
_OF THE THERMOMETER._
This instrument is designed for measuring the increase or decrease of
heat. By doing it numerically, it fixes in our minds the quantity of
fire, which any subject, at any time, is impregnated with. If different
bodies are brought together, though each possesses a different degree
of heat, it teaches us to discover what degree of heat they will
arrive at when thoroughly mixed, supposing effervescence to produce no
alteration in the mixture.
The inventor of this admirable instrument is not certainly known,
though the merit of the discovery has been ascribed to several great
men, of different nations, in order to do them and their countries
honor. It came to us from Italy, about the beginning of the sixteenth
century. The first inventors were far from bringing this instrument
to its present degree of perfection. As it was not then hermetically
sealed, the contained fluid was, at the same time, influenced by
the weight of the air, and by the expansion of heat. The academy of
Florence added this improvement to their thermometers, which soon made
them more generally received; but, as the highest degree of heat of
the instrument, constructed by the Florentine gentlemen, was fixed
by the action of the strongest rays of the sun in their country, this
vague determination, varying in almost every place, and the want of a
fixed universal scale, rendered all the observations made with such
thermometers of little use to us.
Boyle, Halley, Newton, and several other great men, thought this
instrument highly worthy of their attention. They endeavoured to fix
two invariable points to reckon from, and, by means of these, to
establish a proper division. Monsieur des Amontons is said to have
first made use of the degree of boiling water, for graduating his
mercurial thermometers. Fahrenheit, indeed, found the pressure of the
air, in its greatest latitude, would cause a variation of six degrees
in that point; he therefore concluded, a thermometer made at the time
when the air is in its middle state, might be sufficiently exact for
almost every purpose. Long before the heat of boiling water was settled
as a permanent degree, many means were proposed to determine another.
The degree of temperature in a deep cave or cellar, where no external
air could reach, was imagined by many a proper one; but what that
degree truly was, and whether it was fixed and universal, was found too
difficult to be determined. At last the freezing point of water was
thought of, and though some doubts arose, with Dr. Halley and others,
whether water constantly froze at the same degree of cold, Dr. Martine
has since, by several experiments, proved this to be beyond all doubt,
and this degree is now received for as fixed a point as that of boiling
water.
These two degrees being thus determined, the next business was the
division of the intermediate space on some scale, that could be
generally received. Though there seemed to be no difficulty in this,
philosophers of different countries have not been uniform in their
determinations, and that which is used in the thermometer at present
the most common, and, in other respects, the most perfect, is far from
being the simplest.
The liquid wherewith thermometers were to be filled, became the object
of another enquiry. Sir Isaac Newton employed, for this purpose,
linseed oil; but this, being an unctuous body, is apt to adhere to the
sides of the glass, and, when suddenly affected by cold, for want of
the parts which thus stick to the sides, does not shew the true degree.
Tinged water was employed by others; but this freezing, when
Fahrenheit’s thermometer points 32 degrees, and boiling, when it rises
to 212, was, from thence, incapable of denoting any more intense cold
or heat.
Spirit of wine, which endures much cold without stagnating, was next
made use of; but this liquor, being susceptible of no greater degree
of heat than that which, in Fahrenheit’s scale, is expressed by 175,
could be of no service where boiling water was concerned.
At last the properest fluid, to answer every purpose, was found to be
mercury. This had never been known to freeze[6]; and not to boil under
a heat of 600 degrees, and is free from every inconveniency attending
other liquors.
As the instrument is entirely founded on this principle, that heat or
fire expands all bodies, as cold condenses them, there was a necessity
of employing a fluid easy to be dilated. A quantity of it is seated in
one part in the bulb. This being expanded by heat, is pushed forward
into a fine tube, or capillary cylinder, so small, that the motion
of the fluid in it is speedy and perceptible. Some thermometers have
been constructed with their reservoir composed of a larger cylinder;
but in general, at present, they are made globular. The smaller the
bulb is, the sooner it is heated through, and the finer the tube, the
greater will be the length of it, and the more distinct the degrees.
It is scarcely possible that any glass cylinder, so very small, should
be perfectly regular; the quicksilver, during the expansion, passing
through some parts of the tube wider than others, the degrees will be
shorter in the first case, and longer in the latter. If the divisions,
therefore, are made equal between the boiling and freezing points, a
thermometer, whose cylinder is irregular, cannot be true. To rectify
this inconveniency, the ingenious Mr. Bird, of London, puts into the
tube about the length of an inch of mercury; and measuring, with a
pair of compasses, the true extent of this body of quicksilver in one
place, he moves it from one end to the other, carefully observing where
it increases or diminishes in length, thereby ascertaining the parts,
and how much the degrees are to be varied. By this contrivance, his
thermometers are perfectly accurate, and exceed all that were ever made
before.
I shall not trouble my reader with numerous calculations that have been
made, to express the quantity of particles of the liquor contained
in the bulb, in order to determine how much it is dilated. This, Dr.
Martine seems to think a more curious than useful enquiry. It is
sufficient, for our purpose, to know how the best thermometers ought to
be constructed: they who have leisure and inclination, may be agreeably
entertained by the author last cited.
By observing the rise of the mercury in the thermometer, during any
given time, as, for instance, during the time of the day, we ascertain
the degree and value of the heat of every part of the day, from whence
may be fixed the medium of the whole time, or any part thereof. By
repeated experiments, it appears, the medium heat of most days is
usually indicated at eight o’clock in the morning, if the instrument is
placed in the shade, in a northern situation, and out of the reach of
any accidental heat.
Though water is not so readily affected as air by heat and cold, yet,
as all bodies long exposed in the same place, become of the same degree
of heat with the air itself, no great error can arise from estimating
water, in general, to be of the same heat as the air, at eight o’clock
in the morning, in the shade.
The thermometer teaches us that the heat of boiling water is equal to
212 degrees, and by calculation we may know what quantity of cold water
is necessary to bring it to any degree we choose; so, notwithstanding
the instrument cannot be used in large vessels, where the water is
heating, yet, by the power of numbers, the heat may be ascertained with
the greatest accuracy. The rule is this: multiply 212, the heat of
boiling water, by the number of barrels of water thus heated, (suppose
22) and the number of barrels of cold water to be added to the former,
(suppose 10,) by the heat of the air at eight o’clock, (suppose 50,)
add these two products together, and divide by the sum of the barrels;
the quotient shews the degree of heat of the water mixed together.
212 heat of boiling water.
22 barrels to be made to boil.
----
424 50 deg. heat of air at eight.
424 10 barrels of cold water.
---- ---
22 4664 500
10 500
-- ----
sum 32) 5164(161⅓ degrees will be the heat of the water
of barrels 32 when mixed together.
----
196
192
----
44
32
----
12
The calculation may be extended to three or more bodies, provided
they be brought to the same denomination. Suppose 32 barrels of water
to be used where there is a grist of 20 quarters of malt, if these
20 quarters of malt are of a volume or bulk equal to 11 barrels of
water, and the malt, by having lain exposed to the air, is of the same
degree of heat with the air, in order to know the heat of the mash, the
calculation must be thus continued.
161⅓ heat of water 50 degrees of heat of malt
32 barrels of water 11 barrels, volume of malt
---- ---
333 550
483
----
32 water 5163
11 malt 550
-- ----
43 ) 5713 (132 degrees, which will be the heat of
43 the mash.
----
141
129
----
123
86
----
37
We shall meet hereafter with some incidents, which occasion a
difference in the calculations made for the purpose of brewing, but of
these particular mention will be made in the practical part.
The thermometer, by shewing the different degrees of heat of each part
of the year, informs us, at the same time, how necessary it is the
proportions of boiling water to cold should be varied to effect an
uniform intent; also that the heat of the extracts of small beer should
differ proportionably as the heats of the seasons do: it assists us to
fix the quantity of hops necessary to be used at different times; how
much yeast is requisite, in each term of the year, to carry on a due
fermentation; and what variation is to be made in the length of time
that worts ought to boil. Indeed, without this knowledge, beers, though
brewed in their due season, cannot be regularly fermented, and whenever
they prove good, so often may it be said fortune was on the brewer’s
side.
Beers are deposited in cellars, to prevent their being affected by
the variations of heat and cold in the external air. By means of the
thermometer, may be determined the heat of these cellars, the temper
the liquor is kept in, and whether it will sooner or later come forward.
The brewing season, and the reason why such season is fittest for
brewing, can only be discovered by this instrument. It points out
likewise our chance for success, when necessity obliges us to brew in
the summer months.
As all vegetable fermentation is carried on in heats, between two
settled points, we are, by this instrument, taught to put our worts
together at such a temperature, as they shall neither be evaporated by
too great a heat, nor retarded by too much cold.
If curiosity should lead us so far, we might likewise determine, by it,
the particular strength of each wort, or of every mash; for if water
boils at 212 degrees, oil at 600, and worts be a composition of water,
oil and salt; the more the heat of a boiling wort exceeds that of
boiling water, the more oils and salts must it contain, or the stronger
is the wort.
A given quantity of hops, boiled in a given quantity of water, must
have a similar effect, consequently the intrinsic value of this
vegetable may, in the same manner, be ascertained.
The more the malts are dried, the more do they alter in color, from a
white to a light yellow, next to an amber, farther on to a brown, until
the color becomes speckled with black; in which state we frequently see
it. If more fire or heat is continued, the grain will at last charr,
and become intirely black. By observing the degrees of heat necessary
to induce these alterations, we may, by the mere inspection of the
malt, know with what degree of fire it has been dried; and fixing upon
such which best suits our purpose, direct, with the greatest accuracy,
not only the heat of the first mash, but the mean heat the whole
brewing should be impressed with to answer our intent, circumstances of
the greatest consequence to the right management of the process.
If I had not already said enough to convince the brewer of the utility
of this instrument, how curious he ought to be in the choice, and how
well acquainted with the use of it, I should add the heat gained by the
effervescing of malt, is to be determined by it alone; the quantity of
heat lost by mashing, by the water in its passage from the copper to
the mash ton, and by the extract coming down into the underback, these
can be found by no other method; and, above all, that there is no other
means to know with certainty the heat of every extract.
I know very well good beers were sometimes, perhaps often, made before
the thermometer was known, and still is, by many who are entirely
ignorant of it; but this, if not wholly the effect of chance, cannot
be said to be very distant from it. They who carry on this process,
unassisted by principles and the use of the thermometer, must admit
they are frequently unsuccessful, whereas did they carefully and
with knowledge apply this instrument, they certainly would not be
disappointed.—It is equally true, the brewing art, for a long space
of time, has been governed by an ill-conveyed tradition alone; if
lucky combinations have sometimes flattered the best practitioners,
faulty drinks have as often made them feel the want of certain and
well established rules. It is just as absurd for a brewer to refuse
the use of the thermometer, as it would be for an architect to reject
the informations of his plummet and rule, and to assert they were
unserviceable because the first house, and probably many others, were
built without their assistance.
SECTION VII.
OF THE VINE, ITS FRUITS, AND JUICES.
After these short accounts of the principles and instrument necessary
to the right understanding of the brewing art, we should now draw near
to the particular object of this treatise, but as the most successful
method to investigate it, must be first to inspect the great and
similar example nature has set before us, our time will not be lost by
making this enquiry.
Any fermented liquor, that, in distillation, yields an inflammable
spirit miscible with water, may be called wine, whatever vegetable
matter it is produced from.—As beer and ales contain a spirit exactly
answerable to this definition, brewing may justly be called the art
of making wines from corn. Those, indeed, which are the produce of
the grape, have a particular claim to the name, either because they
are the most ancient and the most universal, or that a great part of
their previous preparation is owing to the care of nature itself. By
observing the agents she employs, and the circumstances under which
she acts, we shall find ourselves enabled to follow her steps, and to
imitate her operations.
Most grapes contain juices, which, when fermented, become in time as
light and pellucid as water, and are possessed of fine spiritous
parts, sufficient to cherish, comfort, and even inebriate. But these
properties of vinosity are observed not to be equally perfect in the
fruits of all vines; some of them are found less, others not at all
proper for this purpose. It is therefore necessary to examine the
circumstances which attend the forming and ripening of those grapes,
whose juices produce the finest liquors of the kind.
All grapes, when they first bud forth, are austere and sour, therefore
of a middle nature. And this can be no other than the effect of the
autumnal remaining sap, mixed with the new raised vernal one, the
consequence of which mixture will be found greatly to merit our
inquiry. As far as our senses can judge, at first, it appears that the
juice, in this state, consists of somewhat more than an acid combined
with a tasteless water. When the fruit is ripe, it becomes full of
a rich, sweet, and highly flavoured juice. The color, consistency,
and taste of which shew, that, by the power of heat, a considerable
quantity of oil has been raised, and, sheathing the salts, is the
reason of its saccharine taste and saccharine properties.
In England, grapes are probably produced under the least heat they can
be raised by. They discover themselves in their first shape, about
June, when the medium heat of the twenty-four hour’s shade is 57,60.
This, with what more should be added for the effect of the sun’s
beams, are the degrees of heat which first introduce the juices into
this fruit.
The highest degrees of heat, in the countries where grapes come to
perfect maturity, have been observed to be, in various parts of
Italy, Spain, and Greece 100, and at Montpelier 88, in the shade; to
which, according to Dr. Lining’s observations, 20 degrees must be
added for the effect of the sun’s beams. The greatest heat in Italy
will then amount to 120 degrees, and in the south of France to 108.
These approach nearly to the strongest heats observed in the hottest
climates, which, in Astracan, Syria, Senegal, and Carolina, were from
124 to 126 degrees.
Those countries, where the heat is greatest, in general produce the
richest fruits, that is, the most impregnated with sweet, thick and
oily juices. We are told, among the Tockay wine-hills, there is one
which, directly fronting the south, and being the most exposed to
the sun, yields the sweetest and richest grapes. It is called the
_sugar-hill_, and the delicious wines extracted from this particular
spot, are all deposited in the cellars of the imperial family. Those
grapes, some in the Canaries, some in other places, being suffered to
remain the longest on the tree, with their stems half cut through, by
this means procure their juices to be highly concentrated, and produce
that species of sweet, oily, balmy wines, which, from this operation,
are called _sack_, a derivation of the French word _sec_ or _dry_.
In all distillations of unfermented vegetables, water and acid salts
rise first. A more considerable degree of fire is required for the
elevation of oils, and a still greater one for the lixivial salts,
which render those oils miscible with water.
A plant, exposed to a very gentle heat, at first yields a water which
contains the perfect smell of the vegetable blended with a subtile
oil; if more heat be added, an heavier oil will come over: from some a
volatile alkali, from others a phlegm will rise, which gradually grows
acid; and, last of all, with the farther assistance of fire, the black,
thick, empyreumatic sulphur. Nature, in a less degree, may be said
to place a like series of events before our eyes, in the forming and
maturating of grapes, and it is by imitating what she does, that the
inhabitants of different countries may improve the advantages of their
soil and of their air.
In order to illustrate the doctrine, that grapes are endued with
various properties, in proportion to the heat of the air they have been
exposed to, let us remember what Boerhaave has observed, that, in very
hot weather, the oleous corpuscles of the earth are carried up into the
air, and, descending again, cause the showers and dews in summer to be
very different from the pure snow of winter. The first are acrid, and
disposed to froth, the last is transparent and insipid. Hence summer
rain, or rain falling in hot seasons, is always fruitful, whereas in
cold weather it is scarcely so at all. In winter the air abounds with
acid parts, neither smoothed by oils nor rarified by heat: cold is
the condensing power, as heat is the opener of nature. In summer, the
air, dilating itself, penetrates every where, and gives to the rain
a disposition to froth, occasioned by the admixture of oleous and
aërial particles. Thus the acid salts, either previously existing, or
by the vernal heat introduced into the grapes, and necessary to their
preservation, are neutralized by coming in contact with the juices
the foregoing autumn produced; after which a hotter sun, covering or
blending these juices with oils, changes the whole into a saccharine
form. In proportion as these acids are more or less sharp, and
counterbalanced by a greater or lesser quantity of oils, the juices
of grapes approach more or less to the state of perfection, which
fermentation requires.
There are many places, as Jamaica, Barbadoes, &c. in which experience
shews the vine cannot be cultivated to advantage. By comparing the heat
of these places with those in Italy and Montpelier, it appears this
defect is not owing to excessive heats, but to their constancy and
uniformity; the temperature of the air of these countries seldom being
so low as the degree necessary for the first production of the fruit.
Whenever the cultivation of the vine is attempted in these parts of
the West Indies, the grapes, on their first appearance, are shaded and
skreened from the beams of the sun, which, in their infancy, they are
not able to bear.
Hence we learn, though nature employs both the autumnal and vernal
seasons, yet there are lesser heats with which she prepares the first
juice of grapes, a stronger power of the sun she requires to form the
fruit, and a greater than either to ripen it. We have investigated the
lowest degrees of heat, in which grapes are produced, and nearly the
highest they ever receive to ripen them. Let us call the first the
_germinating_ degrees, and the last those of _maturation_. If nearly
58 be the lowest of the one, and 126 the highest of the other, and
if a certain power of acids is necessary for the germination of the
grapes, which must be counterbalanced by an equal power of oils raised
by the heat of the sun for their maturation, then the medium of these
two numbers, or 92, maybe said to be a degree at which this fruit
cannot possibly be produced, and inferior to that by which it should
be maturated. At Panama the lowest degree of heat in the shade is 72,
to which 20 being added, for the sun’s beams, the sum will be 92, and
consequently no grapes can grow there, except the vines be placed in
the shade.
If we recollect that we can scarcely make wine, which will preserve
itself, of grapes produced in England, we shall be induced to think,
that the reason of this defect is the want of the high degrees of heat.
Our sun seldom raises the thermometer to 100 degrees, and that but for
a short continuance. Our medium heat is far inferior to 92, and hence
we see, at several distant terms in summer, new germinated grapes, but
seldom any perfectly ripe. These observations, the use of which, in
brewing, we will endeavour to apply, likewise point out to us, what
part of our plantations are fit to produce this fruit, and to what
degree of perfection.
A research made for each constituent part forming grapes, as well as
the proportion they bear to one another, at first sight, appears to
be an eligible method to discover the nature of wines; but in every
vegetable their parts are mixed and interwoven, and every degree of
heat, acting on them, finds these so blended, as to render their
division too imperfect for such enquiry to be made with sufficient
accuracy, to deduce therefrom the rules of an art. In the producing,
ripening, and fermenting the juice of the grapes, as well as in forming
beers and ales, the element of fire so superlatively influences
and governs every progressive act, as to occasion some remarkable
difference in their appearance: from, hence, then, we may expect the
information we want, and be enabled to discover the laws by which
Nature forms her wines.
When the constituent parts of a subject are to be estimated by heat
alone, the number of degrees comprehended between the first heat
which formed it, and the last which brought it to a perfect state,
must express the whole of its constituent parts. Complete finished
substances, must have been benefited by the whole latitude of degrees
applicable thereto; and in proportion as part of the whole latitude is
wanting, will their nature be different, and themselves less perfect.
This variety is remarkable in the fruit we are now treating of. A
country endued with the lowest germinating, and with the highest
maturating degrees of heat for grapes, would produce them in the utmost
perfection; that is, they would possess all the several properties they
could obtain from this circumstance; consequently such are capable of
forming wines that would preserve themselves a very long time, and
would also become spontaneously fine. From the several heats we have
observed that this fruit is capable of enduring, it is reasonable to
believe the greatest number of degrees of heat employed to form all
their constituent parts, must be where, during the whole space of
vegetation, the heat in the shade varies from 60 to 106 degrees, and
constitutes a difference of 46 degrees. So great a latitude, ordered by
nature, most certainly denotes the general utility of the plant.
The climate of the southern part of France approaches nearest to this;
but Spanish wines are richer; their grapes are formed by a warmer sun;
their vernal and maturating heats exceed those of France; but, at the
same time, their wines are more stubborn, and, to be made fine, require
the help of precipitation. This variety increases according to the heat
of climates: thus we see wines which come from the coast of Africa,
whose richness and stubbornness are beyond the reach of any menstruum
employed to fine them. Let us endeavour to reduce this apparent
inconstancy to rule, in order to assist our art.—If the lowest heat
which forms the grape, in the southern parts of France, be 60 degrees,
and if 88 degrees, in the shade, be the mean of their maturating heat,
the difference between 60 and 88, or 28 degrees, is the number which
includes the constituent parts of grapes in this country, as these
degrees imply the whole space of their progress. If like juices were to
be imitated by art, as in our hot-houses, it is clear half the number
of the degrees of heat which form the whole of the constituent parts,
or 14, deducted from 74, the mean heat of their whole vegetation, would
give 60, for the first heat to be employed, and this to be raised, for
maturation, to 88, the greatest heat, nature in this case, permits, or
14 degrees to be added to the same whole mean. To liken the wines of
Spain, where the autumnal and vernal heats are greater than in France,
the heat forming the first juices must be more, as also the maturating
heats; but with such practice, the number of constituent degrees would
be found to be fewer, and spontaneous brightness could no more be
expected, than it is found, in their wines.
A strict enquiry after the heats first and last applied to grapes, is
of such consequence to ascertain the principles by which malt liquor
should be formed, that, though grapes produced in England scarcely
make wines which can maintain themselves sound, yet, as the rule is
universal, even from them we shall be able to establish not only its
certainty, but also the application of the number of the degrees found
between the heats which germinate the fruit, and those which ripen them.
From twelve years observation, we have found
the mean heat in the shade, from the 1st of
June, to the 15th, when grapes with us first Deg.
bud forth, to be 57.60
Our greatest heat, under like circumstances,
from the 15th to the 31st of July, to be 61.10
-----
Their difference, 3.50
-----
Their medium, 59.35
-----
If, from their medium, 59.35, we subtract 1.75, half their difference,
or half their constituent parts, we must have left 57.60 for the
germinating heat; and if to their medium, 59.35, we add 1.75, half the
number of their constituent parts, we shall have 61.10, the highest
mean heat, in the shade, at the time the richest juices of our grapes
are formed. It is true, in July, nor even in the following months, when
the heat continues nearly alike, our grapes are not ripe, nor gathered;
the properties raised by our greatest sunshine, as yet have not reached
the fruit, and though the mean heat of the air in September and October
is less, yet it is sufficient to place in the grapes the juices raised
by the preceding hot sun, which concentrate and grow richer, by
remaining on the plant, though, for want of a sufficient heat, they do
not reach that perfection obtained in warmer climates.
The want of grapes in many parts both of America and Africa, and the
reason we gave for this, (See page 55,) warrants the truth of the
division we have just now made, between the germinating and maturating
heats; and if the effects caused by a hot sun do not immediately
benefit the fruit, by a parity of reason, after the grapes are
gathered, the plant must possess, (and surely for some longer space, by
a continued heat, equal, and often superior, to the vernal sun,) juices
which Nature is too frugal not usefully to apply; these juices, we
apprehend, assist in forming the embryo of the leaves which are fully
to expand the ensuing year, and serve, by their oleaginous quality,
to preserve these and the whole plant during the cold of the winter;
which cold, at the same time that it contracts the pores of the vine,
condenses and thickens these richer juices, from whence few, if any of
them, are lost or expended by perspiration. The heat of the following
spring renews their activity, when blending with those this season
attracts, the leaves open, the flowers appear, and the fruit forms.
Thus far we conceive the act of germination extends, provided for and
assisted both by the autumnal and vernal heats, and which, in point of
power, are nearly equal and uniform.
The heat of the sun, during summer months, and if to this we add the
more constant heat at the roots of the vine, retained there by the
density of the earth; these (though superior to the germinating heat)
produce a like uniformity for maturating the fruit: thus nature, in
order to implant in wines an original even taste, and to facilitate
the fermentable act, amidst the great variety that appears to us in
the heat of the air, seems, upon the whole, to act by steady and equal
motions; or rather, perhaps, this is the best manner by which we can
reduce to rule; the inconstancy of the atmosphere.
I am sensible these facts had been represented in a more natural light,
had I observed the degrees of heat impressed on the vine in every
season of the year; the difference of the sun’s heat, in every hour of
the day, a variety exceeding that in the shade; that between night and
day; the aspect of the plant; the heat of the earth at its surface, as
well as at the roots of the vine; all these would have increased the
circumstances to a prodigious extent; which, though perhaps requisite
to satisfy philosophic investigation, might, from their number and
variety, have been the means rather to induce us to error, than to
discover the general rules by which nature acts.
From the above-related process we are taught, that nature, in forming
wines, is not confined to a certain fixed number of degrees, but
admits, for this act, of a considerable latitude, according to the
extent of which the wines vary in taste and properties; and that she
affects an equality of heat in each period of vegetation; from whence
the brewer is taught, if he form his malt-liquors with four mashes,
as in the autumn and spring the vine is impressed with heats nearly
uniform, so ought his two first mashes to be; the third, in imitation
of the high heat of summer, should be much hotter, and the heat of his
last mash the same with this; and this general rule has been found
universally true, for beers expected to preserve themselves sound a
sufficient time; and admits but of a proportional variation, when fewer
or more mashes are employed, as the degrees of heat denominating the
constituent parts of the grain, must be applied in proportion to the
quantity of water used to each mash; but in malt liquors speedily to
be drank, or when we deviate greatly from the more perfect productions
of nature, we are then compelled to swerve from her rules; a practice
never profitable, and which nothing but necessity can justify.
The nature of the soil proper for the vine, might, in another work,
be a very useful enquiry. It will be sufficient here, barely to hint
at the effect, which lixivial soils produce in musts. The Portugueze,
when they discovered the Island of Madeira in 1420, set fire to the
forests, with which it was totally covered. It continued to burn for
the space of seven years, after which the land was found extremely
fruitful, and yielding such wines, as, at present, we have from thence,
though in greater plenty. It is very difficult to fine these wines,
and, though the climate of this island is more temperate than that of
the Canaries, the wines are obliged to be carried to the Indies and the
warmer parts of the globe, to be purged, shook, and attenuated, before
they can arrive to an equal degree of fineness with other wines; were
the Portugueze acquainted with what may be termed the artificial method
of exciting periodical fermentation, much or the whole of this trouble
might be avoided. Hence we see, that soils impregnated with alkaline
salts will produce musts able to support themselves longer, and to
resist acidity more, than other soils, under the same degree of heat.
Grapes have the same constituent parts as other vegetables. The
difference between them, as to their tastes and properties, consists in
the parts being mixed in different proportions. This arises, either
from their absorbent vessels more readily attracting some juices than
others, or from their preparing them otherwise, under different heats
and in different soils.
We find, says Dr. Hales, by the chymical analysis of vegetables, that
their substance is composed of sulphur, volatile salts, water, and
earth, which principles are endued with mutual attracting powers. There
enters likewise in the composition, a large portion of air, which has
a wonderful property of attracting in a fixed, or of repelling in
an elastic state, with a power superior to vast compressing forces.
It is by the infinite combinations, actions, and reactions of these
principles, that all the operations in animal and vegetable bodies are
effected.—Boerhaave, who is somewhat more particular with regard to the
constituent parts of vegetables, says, that they contain an oil mixed
with a salt in form of a sapo, and that a saponaceous juice arises from
the mixture of water with the former.
Thus we see, from the composition of grapes, that they have all the
necessary principles to form a most exquisite liquor, capable, by a
gentle heat, to be greatly attenuated. They abound with elastic air,
water, oils, acid, and neutral salts, and even saponaceous juices.—The
air contained in the interstices of fluids is more in quantity than is
commonly apprehended. Sir Isaac Newton has proved that water has forty
times more pores than solid parts; and the proportion, likely, is not
very different in vegetable juices. When the fruit is in its natural
entire state, the viscidity of the juices, and their being enveloped by
an outward skin, prevent the expansion of the inclosed air; it lies as
it were inactive. In this forced state, it causes no visible motion,
nor are the principles, thus confined, either subjected to any apparent
impressions of the external atmosphere, or so intimately blended as
when they are expressed. A free communication of the external air, with
that contained in the interstices of the liquor, is required to form a
perfect mixture. By what means this is effected, what alterations it
produces, or, in general, in what manner the juice of the grape becomes
wines, must be the subject of our next inquiry.
The process of a perfect fermentation is undoubtedly the same (where
the due proportions of the constituent parts, forming the must,
are exactly kept) whatever vegetable juices it is excited in. For
this reason, we will observe the progress of this act in beers and
ales, these being subjects we are more accustomed to, and where the
characters appear more distinct, in order to apply what may be learned
from thence to our chief object, the business of the brewer.
SECTION VIII.
_OF FERMENTATION IN GENERAL._
Vegetable fermentation is that act, by which oils and earth, naturally
tenacious, by the interposition of salts and heats, are so much
attenuated and divided, as to be made miscible with, and to be
suspended in, an homogeneous pellucid fluid; which, by a due proportion
of the different principles, is preserved from precipitation and
evaporation. According to Boerhaave, a less heat than forty degrees
leaves the mass in an inert state, and the particles fall to the bottom
in proportion to their gravity; a greater heat than eighty degrees
disperses them too much, and leaves the residuum a rancid, acrimonious,
putrid mass.
It is certainly very difficult, if not impossible, to discover the
true and adequate cause of fermentation. But, by tracing its several
stages, circumstances, and effects, we may perhaps perceive the agents
and means employed by nature to produce this singular change; a degree
of knowledge, which, we hope, is sufficient to answer our practical
purposes.
The must, when just pressed from the grapes, is a liquid, composed of
neutral and lixivial salts, oils of different spissitude, water, earth,
and elastic air. These, irregularly ranged, if I may be permitted the
expression, compose a chaos of wine. Soon after the liquor is settled,
a number of air bubbles arise, and at first adhere to the sides of the
containing vessel; their magnitude increases as they augment in number,
so that at last they cover the whole surface of the must.
It has been long suspected, and, if I mistake not, demonstrated, that
an acid, of which all others are but so many different species, is
universally dispersed through, and continually circulating in, the
air; and that this is one of nature’s principal agents, in maturating
and resolving of bodies. Musts, like other bodies, being porous, the
circulating acids very powerfully introduce themselves therein by the
pressure of the atmosphere, in proportion as the pores are more or less
expanded by the heat they are exposed to. The particles of acids are
supposed by Newton to be endued with a great attractive force, in which
their activity consists. By this force, they rush towards other bodies,
put the fluid in motion, excite heat, and violently separate some
particles in such manner as to generate or expel air, and consequently
bubbles.
From hence it appears that, as soon as the acid particles of the air
are admitted into the must, they act on the oils, and excite a motion
somewhat like the effervescence generated, when acids and oils come in
contact, though in a less degree. This motion is the cause of heat, by
which the included elastic air, being rarefied, occasions the bubbles
to ascend towards the surface.—These, by the power of attraction, are
drawn to the sides of the vessel; at first they are small and few,
but increase, both in number and magnitude, as the effect of the air
continues, till, at last, they spread over the whole surface. The
first stage of vegetable fermentation shews itself to be a motion
excited by the acids floating in the air, acting on the oleous parts
of the liquor, which motion gives an opportunity to the divided minute
parts of air, dispersed throughout the whole, to collect themselves
in masses: from hence they become capable to exert their elasticity,
and to free themselves from the must. (See Arbuthnot on air p. 116.)
It may, perhaps, be proper to observe, that all musts, which ferment
spontaneously, contain for this purpose a large portion of elastic air.
Bubbles still continue to rise after the must is entirely covered with
them; and a body of bladders is formed, called, by the brewers, the
_head of the drink_; as the bubbles increase, the head rises in height,
but the oils of the must, being as yet of different spissitudes,
those which are least tenacious soon emit their air; others, somewhat
stronger, being rarefied by the fermenting heat, rise on the surface
higher than the rest, while such aerial bubbles as are more dense,
take their place below them. From hence, and from the constituent
parts of the drink not being as yet intimately mixed, the head takes
an uneven and irregular shape, and appears like a beautiful piece of
rock work. After this, it requires some time, and it is by degrees,
that the particles dispose themselves in their due order, to be
farther attenuated by the act of fermentation, which, when effected,
the saline, oily, and spiritous parts become perfectly miscible with
the water. The head of the liquor then is more level; heterogeneous
bodies, as dirt, straw, corks, &c. assisted by bubbles of air adhering
to them, are now buoyed on the surface, and should be skimmed off,
lest, when the liquor becomes more light and spiritous, they should
subside. About this time, such parts of the must as are too course to
be absorbed in the wine (as they consist chiefly of pinguious oils,
mixed with earth, though they strongly envelope much elastic air) from
their weight, sink to the bottom, and form the lees. But the internal
motion increasing, the air bubbles grow larger; some, not formed of
parts so strong as the others, which generally are the first, burst and
strengthen the rest; and thereby a heat is retained in the fermenting
liquor, which carries the act on to a farther degree. The particles of
the must become more pungent and spiritous, because more fine and more
active; some of the most volatile ones fly off; hence, that subtle and
dangerous vapor, called _gas_, which extinguishes flame and suffocates
animals. The wine, by these repeated acts, being greatly attenuated,
is at last unable to support, on its surface, the weight of such a
quantity of froth, rendered more dense by the repeated explosions of
the air bubbles. Now, lest the liquor should be fouled by the falling
in of the froth, it is put in vessels having only a small aperture,
where it continues to ferment, with a slower and less perceptible
motion, which gradually diminishing until it reaches the period when it
neither attracts or repels air, it admits of its communication with it
to be cut off; not that thereby, in a strict sense, the fermentation
can be said to be completely ended: the least heat is sufficient to
renew, or rather to continue the act, more especially if by any means
the atmosphere can gain any admittance, however small.
The alteration caused in the liquor, by the pressure of the external
air, from the very first of its fermenting, not only occasions the
particles of the must to form themselves in their due order, but also,
by the weight and action of that element, grinds and reduces them into
smaller parts. From hence they more intimately blend with each other,
the wine becomes of an equal and even taste, and if the constituent
parts of the must be in a perfect proportion, it will continue to
ferment, until, these being disposed and ranged in right lines, a fine
and pellucid fluid is produced.
That this operation subsists, even after the liquor becomes fine, is
evident; for every fretting is a continuance of fermentation, though
often almost imperceptible. Thus, the component parts of the liquor are
continually reduced to a less volume, the oils become more attenuated,
and less capable of retaining elastic air. As these frettings are often
repeated, it is impossible to determine, by any rule, the exact state
in which wine should be, in order to be perfect for use. It would seem,
however, that the more minutely the parts are reduced, the more their
pungency will appear, and the easier their passage be in the human
frame. Both wines and beers, when new, possess more elastic air, than
when meliorated by age; to be wholesome, they must be possessed of the
whole of the fermentable principles. For these reasons, beers and ales,
when substituted for wines in common, and more especially when given
to the sick, should always be brewed from entire malt: for the last
extracts, possessing but the inferior virtues of the grain, have by so
much less the power to become light, spiritous, and transparent.
Wines never totally remain inactive; fermentation in some degree
continues, and in time the oils, by being greatly attenuated,
volatilise, fly off, and permit a readier admission of the external air
into the drink. In proportion as this circumstance takes place, the
latent acids of the liquor shew themselves, the wine becomes sour, and
in this state is termed vinegar.
Its last stage or termination is, when the remaining active principles,
which the vinegar possessed, being evaporated in the air, a pellicle
forms itself on the surface of the liquor, and dust and seeds,
which always float in the atmosphere, depositing themselves thereon,
strengthen this film into a crust, on which grows moss, and many other
small plants. These vegetables, together with the air, exhaust the
watery parts; after which no signs of fermentable principles remain
but, like the rest of created beings, all their virtues being lost,
what is left is a substance resembling common earth.
Upon the whole, then, it appears, that a liquor fit for fermentation
must be composed of water, acids smoothed over with oils, or saccharine
salts, and a certain portion of elastic air; the heat of the air
the liquor is fermented in, must be in proportion to the density
of its oils; and lastly, that the pores are to be expanded by slow
degrees, lest the air, by being admitted too hastily, should cause an
effervescence rather than a fermentation, and occasion the whole to
become sour. Wines, therefore, fermented in countries where the autumn
is hot, require their oils to be more pinguious, than where the season
is cooler. For the same reason beers are best made, when the air is at
forty degrees of heat, or below the first fermentable point, because
the brewer, in this case, can put his wort to work, at a heat of his
own chusing, which will not be increased by that of the air; on the
contrary, when, by its internal motion, the heat becomes greater, it
will again be abated and regulated by the cold of the medium.
The pores of a wort are expanded in proportion to the heat it is
impressed with; on which account common small beer, brewed in summer,
when the air and acids more easily insinuate themselves into the
liquor, ought to be enriched with oils obtained by hotter extracts, to
sheath these salts; and in winter the contrary method must be pursued.
From this history of fermentation, we can, with propriety, account
for the many accidents and varieties that accompany this act; and a
comparative review of some of them may not be unnecessary.
A cold air, closing the pores of the liquor, always retards, and
sometimes stops, fermentation; heat, on the contrary, constantly
forwards this act; but, if carried too high, immediately prevents it.
A must, loaded with oils, will ferment with more difficulty than one
which abounds with acids; it likewise is longer before it becomes
perfectly fine; but, when once so, will be more lasting.
If the quantities of oil are increased, they will exceed the power both
of the acids naturally contained in the must, and of those absorbed
from the air in fermenting; the liquor will therefore require a longer
time before it becomes pellucid, unless assisted by precipitation: and
there may be cases where even precipitation cannot fine it.
These considerations naturally lead us to a general division of
wines into three classes: First, of such as soon grow fine, and soon
become acid, being the growth of cold countries. Secondly, of those
which, by a due proportion of heat, both when the grapes germinate,
and when they come to maturity, form a perfect must; and not only
preserve themselves, but, in due time, (more especially when assisted
by precipitation,) become transparent; and, thirdly, of such as, having
taken their first form under the highest degrees of _germination_, (as
I termed them) are replete with oils, disappoint the cooper, and render
the application of menstruums useless, unless in such quantities as to
change the very nature of the wine.
This remarkable difference in wines appears chiefly to arise from the
climate; and it will confirm the observation before made, that, as
wines are neither naturally nor uniformly perfect, they must be subject
to many diseases.
All vegetable substances possess fermentable principles, though
in a diversity of proportions; for those juices only, whose
constituent parts approach to the proportion necessary for the act of
fermentation, can be made into wines. I would not, however, from what
I have attributed to a difference of heat in different climates, be
understood, as if I thought that vegetables are more or less acid, more
or less sulphureous, or in general more or less fermentable, merely
from the heat of the country they grow in. This, though likely one
of the principal causes of their being so, is by no means the only
one; the form and constitution of the plant is another. In very hot
climates, we find acid fruits, such as limes, tamarinds, lemons, and
oranges; the proportions of fermentable principles in these fruits
are such, as to render them incapable of making sound wines, though
their juices may, in some degree, be susceptible of fermentation. In
countries greatly favored by the sun, some vines and other fruit trees
there are, which attract the acids from the air, and possibly from the
earth, so greedily, that, when their juices are fermented, they soon
become sour. On the contrary, in cold climates, we see warm aromatic
vegetables grow, as hops, horse-raddish, camomile, wormwood, &c. whose
principles cannot, without difficulty, and perhaps not perceptibly, be
brought to ferment. But these instances must be accounted the extremes
on each sides; for in cold, as well as in hot countries, fruits are
produced susceptible of a perfect natural fermentation: with us, for
example, apples; some species of which are endued with such austere and
aromatic qualities, that their expressed juices ferment spontaneously,
until they become pellucid, and are capable of remaining in a sound
state many years. From hence it appears, that proper subjects, which
will naturally ferment, for making wines, may be found in almost every
climate. England, says Boerhaave, on this account, is remarkably
happy: her fruits are capable of producing a great variety of wines,
equal in goodness to many imported, were not our tastes but too often
subservient, not to reason, but to custom and prejudice.
A similar want of perfection to that observed in wines, may be noticed
in our beers and ales, and it chiefly has its origin in the different
degrees of heat the malt has been impressed with, both in drying
and extracting; where, in the processes of malting and brewing, a
sufficient heat has not been maintained, the liquor undoubtedly must
become acid; in proportion as the contrary is the case, or that the
beer is overcharged with hops, if this is in no great excess, it
retains still a greater tendency to fermentation than to putrefaction,
acids not being wanting, but only enveloped. In this case, time will
get the better of the disease; like to the wines made from the growth
of too hot a sun, these liquors, at a certain period, sicken, smell
rancid, and have a disagreeable taste, but, by long standing, they
begin to fret, and, receiving more acids from the air, recover their
former health, and improve in taste.
But should the quantity of oils exceed this last proportion, in wines
formed from corn, the must, instead of fermenting, would putrify, even
though, by some means, elastic air has been driven into them. In this
case, the over proportion of the oil, and its tenacity, prevents the
entrance of the acids, the wort receives no enlivening principle from
without, and the air, at first conveyed into it, is enveloped with oils
so tenacious as to be incapable of action. Nothing so much accelerates
putrefaction as heat, moisture, and a stagnating air; and all
substances corrupt, sooner or later, in proportion to the inactivity of
the contained air, to the want of a proper vent, and to the closeness
of their confinement. Besides these cases, beers and ales, as well as
wines, sometimes are vapid and flat, without being sour; this does not
so much arise from the imbibing the air of the atmosphere, as from
their fermenting, generating and casting off too much air of their own.
To prevent this accident, they are best preserved in cool cellars,
where their active invigorating principles are kept within due bounds,
and not suffered to fly off. These facts ought to convince us of the
truth, deduced by Dr. Hales, from many experiments, that there is a
great plenty of air incorporated in the substance of vegetables, which,
by the action of fermentation, is roused into an elastic state, and is
as instrumental to produce this act, as it is necessary to the life and
being of animals.
I should here close this short and imperfect account; but as, in the
art of brewing, there is no part so difficult, and at the same time so
important to be in some measure understood, as the cause and effects of
fermentation; and as the examination of this act, in all the different
lights in which it offers itself to our notice, can hardly be thought
uninteresting, these few detached thoughts I hope will be allowed of.
The effect of the act of fermentation on liquors is, so to attenuate
the oils; as to cause them to become spiritous, and easily inflammable.
When a wine is dispossessed of such oils, which is nearly the case
in vinegar, far from possessing a heating or inebriating quality,
it refreshes and becomes a remedy against intoxication. The term of
fermentation ought, perhaps, only to be applied to that operation which
occasions the expressed juices of vegetables to become wine: but as
several acts have assumed the same name, it may not be improper here to
notice the difference between them.
Vegetation, one of them, is that operation of nature wherein more air
is attracted than repelled. I believe all that has been said above,
concerning the juice of grapes, is a convincing proof thereof.
Fermentation is, where the communication of the external and internal
air of a must is open, and in a perfect state; when the power of
repelling, is equal to that of attracting, air.
Putrefaction is when, by the power of strong oils, or otherwise, the
communication between the external and the internal air of the must is
cut off, so that the liquor neither attracts the one nor repels the
other, but, by an intestine motion, the united particles separate and
tend to fly off.
Effervescence is when, by the power of attraction, the particles of
matter so hastily rush into contact, as to generate a heat which expels
the enclosed air; and this more or less in proportion to the motion
excited.
SECTION IX.
_OF ARTIFICIAL FERMENTATION._
By what has been said, it appears, that, though fermentation is
brought on by uniform causes, and productive of similar effects, it is
subject to many varieties, both in respect to its circumstances and to
its perfection. One difference is obvious, and seems to deserve our
attention, as it furnishes a useful division between _natural_ and
_artificial_ fermentation. The first rises spontaneously, and requires
nothing to answer all the necessary purposes, but the perfection of the
juices, and the advantage of a proper heat. The other, at first sight
less perfect, wants the assistance of ferments, or substitutes, without
which the act could, either not at all, or very imperfectly, be excited.
There are undoubtedly liquors, which, though they have of themselves a
tendency to fermentation, and are naturally brought to it, yet, from
some defect in the proportions of their constituent parts, either do
not acquire a proper transparency, or cannot maintain themselves in a
sound state for a sufficient time. These disadvantages, inbred with
them, can hardly ever be entirely removed; they gain very little,
especially the latter, from age, and therefore are really inferior
to liquors, which require the assistance of substituted ferments,
to become real wines. In some artificial fermentations, the ferments
are so duly and properly supplied, and so intimately blended with
the liquor, that in the end they approach very near to, and even vie
with, the most perfect natural wines. Were I to enter into a more
minute detail, it might be shewn, that wines, when transported from a
hot climate to a cold one, are often hurt and checked in the progress
of the repeated frettings they require; from whence they become or
remain imperfect, unless racked off from their grosser lees, or
precipitated with strong menstruums; whereas beers may be so brewed, as
to be adapted either to a hot or a cold region, not only without any
disadvantage, but with considerable improvements.
Hitherto I have considered grapes as a most pulpous fruit, sufficient
to furnish the quantity of water necessary for extracting its other
parts; but the natives of the countries where this fruit abounds, in
order to preserve them, as near as possible in their primitive state,
after they are gathered, suspend them in barns, or place them in ovens,
to dry. Thus, being in great measure divested of their aqueous parts,
these grapes remain almost inactive, and without juices sufficient to
form wines.
In all bodies, the various proportions of their constituent parts
produce different effects; hence they remain more or less in a durable
state, and tend either to inaction, fermentation, or putrefaction.
Now, by a judicious substitution of such parts as shall be wanting,
they are nearly, if not wholly, restored to their pristine nature,
as may be proved by the observations and experiments communicated to
the public by Dr. Pringle. Thus grapes, though dried and exported
from their natural climate to another, by the addition of water only,
ferment spontaneously, and form wines very near alike to such as
they would have produced before. It may, with confidence, be said,
that, when any considerable difference appears, it arises from the
injudicious manner in which the water is administered, from the fruit
not being duly macerated, or from want of such heat being conveyed
to the water and fruit, as the juices would have had, if they had
been expressed out of the grapes when just gathered; often from the
whimsical mixture of other bodies therewith, and perhaps too from the
quantity of brandy, which is always put to wines abroad, to prevent
their fretting on board a ship. Upon the whole, though, from what
just now has been observed, some small difference must take place, it
rather proves than contradicts the fact, that, a due quantity of water
being applied to dry raisins, an extract may be formed, which will
be impregnated with all the necessary constituent parts the grapes
had in them when ripe upon the vine, consequently will spontaneously
ferment, and make a vinous liquor. Water then, in this case, becomes a
substitute, and the liquors produced in this manner may be accounted
of the first class of artificial wines.
Vegetables, in their original state, are divisible into the pulpous and
farinaceous kinds, both possessing the same constituent parts, though
in different proportions. If from the farinaceous such parts be taken
away as they superabound in, and others be added, of which they are
defective, these vegetables may, by such means, be brought to resemble,
in the proportion of their parts, more especially in their musts,
the natural wines I have before been treating of: and these being
universally acknowledged to be the standard of wines, the nearer any
fermented liquor approaches thereto, by its lightness, transparency,
and taste, the greater must its perfection be.
To enquire which of the pulpous or which of the farinaceous kinds of
vegetables are fittest for the purpose of wine-making, would here be
an unnecessary digression. Experience, the best guide, hath, on the
one side, given the preference to the fruit of the vine, and on the
other to barley. To make a vinous liquor from barley, having all the
properties of that produced from the grape, is a task, which can only
be compassed by rendering the wort of these, similar to the must of the
other.
As malt liquors require the addition of other substitutes, besides
water, to, become perfect wines, they can only be ranked in the
_second_ class of _artificial_ fermentation. These substitutes are
properly called _ferments_, and merit the brewer’s closest attention.
Ferments, in general, such as yeast, flowers or lees of wine, honey,
the expressed juices of ripe fruits, are subjects more or less replete
with elastic air, and convey the same to musts, which stand in need
thereof. Boerhaave has ranged these, and several others, in different
classes, according to their different powers, or rather in proportion
to the quantity of air they contain for this purpose.
The juice of the grape, when fermented, forms more lees than the
extracts of malt. May we not, from thence, infer that, in the fruit,
the elastic air is both more abundant, and contained in a greater
number of stronger, though smaller, vesicles, than it is in the malt?
The barley, being first saturated with water, germinated only, and then
dried with a heat far exceeding that which ripened it, or that which
fermentation admits of, has its air in part driven out. The expulsion
of air from the worts of beers and ales is still farther effected by
the long boiling they undergo. Hence the necessity of replacing the
lost elastic air, in order that these extracts may become fermentable.
This is effected by means of the yeast, which, consisting of a
collection of small bubbles, filled with air, and ready to burst by a
sufficient heat, becomes the ferment, which facilitates the change of
the wort into a vinous liquor.
The musts of malt generally produce two gallons of yeast from eight
bushels of the grain, whereas, in the coldest fermentable weather,
and for the speediest purpose, one gallon of yeast is sufficient to
work this quantity of malt. Much elastic air still remains in beer, or
wine from corn, after the first part of the fermentation is over; for
the liquor, separated from the yeast above mentioned, is, at the time
of this separation, neither flat, vapid, nor sour; but as yeast, the
lees and flowers of malt liquors are of a weaker texture than those
of grapes, all artificial fermentations should be carried on in the
coolest and slowest manner possible: and beers, but more especially
such as are brewed from high-dried, brown malts, (the heat of whose
extracts approaches much nearer to that which dried the grain, than is
the case in brewing pale malt) ought not to be racked from their lees,
as it is frequently practised for natural wines, unless, on account
of some defect, they are to be blended with fresh worts under a new
fermentation.
As all ferments are liable to be tainted, great care ought to be
taken in the choice of them, every imperfection in the ferment being
readily communicated to the must. It would not, therefore, be an
improper question to be determined by physicians, whether, in a time
of sickness, the use of those which have been made in infected places
ought to be permitted, and whether, at all times, a drink fermented in
a pure and wholesome air is not preferable to that which is made among
fogs, smoke, and nauseous stenches.[7]
Wines from corn are distinguished by two appellations, viz., those of
ale and beer. As each of these liquors have suffered in character,
either from prejudice or want of a sufficient enquiry, it may be proper
to levy the objections made against their use, before we enquire into
the means of forming them. The most certain sign of the wholesomeness
of wines is transparency and lightness; yet some, which are rich,
more especially ales, though perfectly fine, have been said to be
viscid.—Transparency appears indeed in many wines, before the oils
are attenuated to their highest perfection, and some viscidity may
therefore be consistent with some degree of brightness. Where the
power of the oils and the salts are equal, which is denoted by the
transparency of the liquor, viscidity can only arise from the want of
age: this cannot be said to be a defect in, but only misapplication of
the liquor, by being used too soon.
That beers retain igneous or fiery particles, seems equally a mistake.
Malt dried to keep, has undoubtedly its particles removed by fire, so
far as the cohesion of them is thereby destroyed, otherwise it would
not be in a fit state to preserve itself sound, or readily to be
extracted. For this reason, when the grain comes in contact with the
water, which is to resolve it, an effervescent heat is generated, which
adds to the extracting power, and should be looked on by the brewer as
an auxiliary help; but it is impossible that the malt, or the must,
should ever inclose and confine the whole or part of fire employed to
form them. Fire is of so subtile a nature, that its particles, when
contained in a body, continually tend to fly off, and mix with the
surrounding air; so that only an equal degree, with what is in the
atmosphere, can be continued in the grain, or any liquor whatever,
after it has been, for some time, exposed thereto.—Brown beers, made
from malt more dried than any other, from experience, are found to
be less heating than liquors brewed from pale malt; which probably
arises from hence, that brown beers contain a less quantity of elastic
air than pale beers, as pale malt liquors contain less than wines,
produced from vegetables in their natural state: and as malt liquors
contain their elastic air in bubbles of a weaker consistence than those
made from the juices of the grape, the effect of beer, when taken in
an over-abundant quantity, is neither of so long a continuance, nor
so powerful as that of wine, supposing the quality and quantity of
each to be equal. This may appear to some persons to be the effect of
prejudice, yet it is but a justice due to the produce of my country,
to add, that some physicians have given it as their opinion, that
strong drinks from malt are less pernicious than those produced from
grapes. As far as these gentlemen have, I hope I may advance, without
being thought guilty of assuming too much, or countenancing debauch, by
pointing out the wines that occasion the fewest disorders.
SECTION X.
_OF THE NATURE OF BARLEY._
Barley is a spicated, oblong, ventricose seed, pointed at each end,
and marked with a longitudinal furrow. The essential constitution
of the parts, in all plants, says Dr. Grew, is the same: thus this
seed, like those which have lobes, is furnished with radical vessels,
which, having a correspondence with the whole body of the corn, are
always ready, when moistened, to administer support to the plume of
the embryo, usually called the _acrospire_. These radical vessels,
at first, receive their nourishment from a great number of glandules
dispersed almost every where in the grain, whose pulpous parts strain
and refine this food, so as to fit it to enter the capillary tubes; and
such an abundant provision is made for the nourishment of the infant
plant, that the same author says, these glandules take up more than
nine tenths of the seed.
Barley is sown about March, sooner or later, according to the season
or soil that is to receive it, and generally housed from ten to twenty
weeks after. Most plants, which so hastily perform the office of
vegetation, are remarkable for having their vessels proportionably
larger; and that these may be thus formed, the seed must contain a
greater quantity of tenacious oils, in proportion to those seeds, whose
vessels being smaller, require more time to perform their growth and
come to maturity. This grain, as may be observed, grows and ripens with
the lower degrees of natural heat; from whence, and from the largeness
of the size of its absorbent vessels, it must receive a great portion
of acid parts. It is said to be viscid, though, at the same time, a
great cooler, water boiled with it being often drunk as such; and,
however it be prepared, it never heats the body when unfermented.
From these circumstances, of its being viscous and replete with acids,
it would at first appear to be a most unfit vegetable, from which
vinous liquors, to be long kept, should be made; and, indeed, the
extracts from it, in its original state, are not only clammy, but soon
become sour.
When the grain is at full maturity, its constituent parts seem to be
differently disposed than when in a state of vegetation. By germination
alone all its principles are put in action; the fibrous parts possess
themselves of a great quantity of tenacious oils, leaving the glandules
and finer vessels replete with water, salts, and the purest sulphur.
If, in this state, the corn is placed in such a situation, that, by
heat, the acid and watery parts may be evaporated, the more such heat
is suffered to affect it, the more dry, and less acid, will the corn
become; its parts will be divided—its viscidity removed; its taste
becomes saccharine, by the acids being sheathed or covered over with
oils; and these last be rendered more tenacious in proportion to
the greater quantity of heat they are made to endure. This process,
regularly carried on, is termed _malting_, and will hereafter be
explained more at large.
But, before we enter thereon, it is necessary to consider the state
of the grain as it comes from the field.—When mowed, though, upon the
whole, it may be said to be ripe, yet every individual part, or every
corn, cannot be so. In some seasons, this inequality is so remarkable,
as to be distinguished by the eye. The difference in the situation,
the soil, and the weather, the changes of the winds, the shelter some
parts of the field have had from such winds, are sufficient to account
for this, and a much greater variety. When the greater part of the
corn is supposed to have come to maturity, it is cut and stacked; the
ripest parts having the least moisture, and the fewest acids, as the
greenest abound in both. In this state the unripe grains of the corn
communicate, to such as are more dry, their moisture and acid parts,
which, coming in contact with their oils, an agitation ensues, more or
less gentle, in proportion to the power of the acids and water; and
from hence is generated a heat, the degree whereof is with difficulty
determined.
When this sweating in the mow is kept within its proper limits, the
whole heap of the corn, after this internal emotion is over, becomes of
one equable dryness, and is not discoloured; but if the grain be put
together too wet or too green, the effervescence occasioned thereby
will produce such a violent intestine heat, as to charr and blacken the
greatest part thereof, nay often make it burst into actual flame.
The effect which a moderate and gentle heat has on the corn, is that of
driving the oils towards the external parts of its vessels and skin:
by this means, it becomes more capable to preserve itself against the
injuries of the weather. The more it is in this state, the backwarder
will it be to germinate, when used to this purpose; and if this act is
carried too far, or to somewhat like what we have just now mentioned,
the plume and root of the enclosed embryo must be scorched, the corn
become inert, and incapable of vegetation. This effect is produced by a
motion sufficient to remove the particles of the grain from each other
beyond their sphere of attraction; and the heat, by which this motion
is excited, has been found, in malted corn, to be at about 120 degrees.
It is likely, that vegetables, in general, are susceptible of a large
latitude in this respect, according to their different textures. The
degree of heat just now mentioned may, perhaps, be applicable to barley
alone; the seeds of some grapes endure 126 degrees of heat, and may
be capable of being impressed with more, and yet vegetate. But, with
corn, if their oils have endured so great a heat, as thereby to be
discolored, the seed can by no means be revived. The color of the grain
properly indicates the healthy state of the embryo, or future plant;
but this, more immediately, is the business of the farmer and maltster,
than that of the brewer.
Thus, though it may be disadvantageous to the maltster to steep grain
which has not sweated in the mow, as, for want of this, it will not
equally imbibe the water; so barley, that is over-heated, or _mow
burnt_, cannot be fit for his purpose. It is, in fact, scarcely
possible that any large quantity of barley, from the same stack,
should make equally perfect malt, as, on its being put together, the
heat generated is always greatest in the centre of the rick, and
considerably more there than in its exterior parts.
SECTION XI.
_OF MALTING._
This process is intended to furnish proper means, for setting the
constituent principles of the grain in motion: so that the oils, which
before served to defend the several parts, may be enabled to take their
proper stations.—This is effected by steeping the barley in water,
where it strongly attracts moisture, as all dry bodies do; but it
requires some time before the grain is fully saturated therewith.[8]
Two or three days, more or less, are necessary, in proportion to
the heat of the air; for vegetables receive the water only, by its
straining through the outward skin, and absorbent vessels, and their
pores are so very fine, that they require this element to be reduced
almost to a vapor, before it can gain admittance. Heat hath not only
the property of expanding these pores, but perhaps also that of adding
to the water a power more effectually to insinuate itself.
By the water gaining admittance into the corn, a great quantity of
air is expelled from it, as appears from the number of bubbles which
arise on its surface when in contact with the grain, though yet much
remains therein. A judgment is formed that the corn is fully saturated,
so as not to be able to imbibe any more water, from its turgidity and
pulpousness, which occasions it readily to give way to an iron rod
dropped perpendicularly therein. At this time the water is let to
run, or drawn off, the grain taken out of the cistern, and laid in a
regular heap, in height about two feet. We have before accounted why
moist vegetables, when stacked together, grow hot; so doth this heap
of barley. The heat, assisted by the moisture, puts in motion the
acids, oils, and elastic air remaining in the corn, and these not only
mollify and soften the radical vessels, but, with united power, force
the juices from the glandular parts into the roots, which are thereby
disposed to expand themselves, and impowered to convey nourishment
to the embryo enveloped in the body of the grain. The corn in this
heap, or couch, is however not suffered to acquire so great a degree
of heat, as to carry on germination too fast, by which not only the
finer but also the coarser oils would be raised and entangled together,
and the malt when made become bitter and ill tasted; but before the
acrospire is perceived to lengthen, the barley is dispersed in beds
on the floor of the malt house, and, from being at first spread thin,
gradually, as it dries, and as the germination is thereby checked in
its progress, it is thrown into larger bodies; so that, at the latter
part of this operation, which generally employs two days, much of the
moisture is evaporated, its fibres are spread, and the acrospire near
coming through the outward skin of the barley. By these signs the
malster is satisfied that every part of the barley has been put in
motion and separated. It is of great consequence, in making of malt,
that the grain be dried by a very slow and gradual heat: for this
purpose it is now thrown into a large heap, and there suffered to grow
sensibly hot, as it will in about 20 or 30 hours: thus prepared for
drying, in this lively and active condition, it is spread on the kiln;
where, meeting with a heat superior to that requisite for vegetation,
its farther growth is stopped; though, in all probability, from the
gentleness of the first fire it ought to be exposed to, none of the
finer vessels are, by this sudden change, rent or torn, but, by drying,
only the cohesion of its parts removed, rendered inactive, and put in a
preservative state. Often, to a fault, the drying of a kiln of malt is
performed in 6 or 8 hours: it would be to the advantage of the grain
that more than double this time was employed for any intent whatever.
It may here be observed, that those oils, which in part form the roots,
being with them pushed out from the body of the corn, and dried by
heat, are lost to any future wort, not being soluble in water; which is
likewise true of those oils which are contained in the shoot or plume;
so that the internal part of the malt has remaining in it a greater
proportion of salts to the oils than before, consequently are less
viscid, more saccharine, and easier to be extracted.
In this process, the acid parts of the grain, though they are the most
ponderous, yet being very attractive of water, become weaker, and, by
the continued heat of the kiln, are volatilized and evaporated with the
aqueous steam of the malt. Thus, by malting, the grain acquires new
properties, and these vary at the different stages of dryness; in the
first it resembles the fruits ripened by a weaker sun, and in the last
those which are the growth of the hottest climates.
When the whiteness of the barley has not been greatly changed by the
heat it has been kept in, it is called pale malt, from its having
retained its original color; but when the fire in the kiln has been
made more vehement, or kept up a longer time, it affects both the
oils and the salts of the grain, in proportion to the degree of the
heat, and to the time it has been maintained, and thus occasions a
considerable alteration in the color. Actual blackness seldom is,
and ought never to be, suffered in malts; but in proportion to the
intenseness of the fire they have been exposed to, the nearer do they
come to that tinge, and from the different brown they shew, receive
their several denominations.
The condition the barley was gathered in, whether green or ripe, is
also clearly discernible when it is malted. If gathered green, it
rather loses than gains in quantity; for the stock of oils in unripe
corn being small, the whole is spent in germination, from whence the
malt becomes of a smaller body, appears shrivelled, and is often
unkindly, or hard. That, on the contrary, which hath come to full
maturity, increases by malting, and if properly carried through the
process, appears plump, bright, clean, and, on being cracked, readily
yields the fine mealy parts, so much desired by the brewer.
The malts, when dried to the pitch intended by the maker, are removed
from the kiln into a heap. Their heat gradually diminishes, and, from
the known properties of fire, flies off, and disperses itself in the
ambient air, sooner or later, as the heap is more or less voluminous;
perhaps too in some proportion to the weight of the malt, and as
the fire has caused it to be more or less tenacious. Nor can it be
supposed that any of its parts are capable of retaining the fire in
such a manner as not to suffer it to get away. So subtile an element
cannot be confined, much less be kept in a state of inactivity,
and imperceptible to our senses. Bars of iron, or brass, even of a
considerable size, when heated red hot, cool and lose their fire,
though their texture is undoubtedly much closer than that of malt or
barley. The experiments made by Dr. Martine, on the heating and cooling
of several bodies, leave no room to doubt of this fact, which I should
not be so particular about, nor in some measure repeat, was it not to
explain the technical phrase used by brewers, when they say, _malts
are full of fire, or want fire_. Hence a prejudice hath by some been
conceived against drinks made from brown malts, though they have been
many months off the kiln, and have no more heat in them, either whole
or ground, than the air they are kept in. The truth of the matter
is, that, in proportion as malts are dried, their particles are more
or less separated from one another, their cohesion is thereby broke,
and, coming in contact with another body, such as water, strongly
attract from it the uniting particles they want. The more violent this
intestine motion is, the greater is the heat just then generated,
though not durable. An effect somewhat similar to what happens on malt
being united with water, must occur on the grain being masticated;
and the impression made on the palate most probably gave rise to the
technical expression just taken notice of.
The minute circumstances of the process of malting will be more readily
conceived from what will hereafter be said. The effects that fire
will have, at several degrees, on what, from having been barley, is
now become malt, are more particularly the concern of the brewer; and
that these differ, both as to the color and properties, is certain.
A determinate degree of heat produces, on every body, a certain
alteration, and hence, as the action of fire is stronger or weaker, the
effect will not be the same as what it would have been in any other
degree.
Barleys, at a medium, may be said to lose, by malting, one fourth part
of their weight, including what is separated from them by the roots
being skreened off: but this proportion varies, according as they are
more or less dried.
As the acrospire, and both the outward and inward skins of the grain
are not dissoluble in water, the glandular or mealy substance is
certainly very inconsiderable in volume and weight: but as in this
alone are contained the fermentable principles of the grain, it
deserves our utmost attention.
We have before seen, that wines, beers, and ales, after the first
fermentation, are meliorated through age by the more refined and gentle
agitations they undergo, and which often are not perceptible to our
senses. To secure this favorable effect, we must form worts capable of
maintaining themselves, for some time, in a sound state. This quality,
however, if not originally in the malt, is not to be expected in the
liquor. Some objections have been raised against this method of
arguing, and these aided by prejudices, often more powerful than the
objections themselves. It is therefore necessary, as malting may be
esteemed the foundation of all our future success, to enquire after the
best and properest methods of succeeding in this process. Let us, for
this purpose, reassume the consideration of the grain, as it comes from
the mow, trace it to the kiln, and observe every change it undergoes
by the action of the fire, from the time that it receives the first
degree of preservation, to that when it is utterly altered and nearly
destroyed.
Barley in the mow, though there its utmost heat should not much exceed
100 degrees, may be extracted or brewed without malting. This the
distiller’s practice daily evinces; but then the extracts, made from
this unchanged corn, are immediately put in the still after the first
fermentation, else they would not long remain in a sound state. Nor
is this method practicable in summer time, as the extracts would turn
sour, before they were sufficiently cooled to ferment. It is true,
by this means, all the charge of the malt duty is saved; but our
spirits thereby are greatly inferior to those of the French.—Boerhaave
recommends the practice of that nation, which is to let the wines
ferment, subside, and be drawn off fine from the lees, before they are
distilled. Was this rule observed in England, distillation would be
attempted only from malted grain, which, if properly extracted for
this purpose, the difference in the spirit would soon shew how useful
and necessary it is to give wines (either from grapes or corn) time to
be softened, and to gain some degree of vinosity before they are used
to this intent.
But might not barleys be dried without being germinated? Undoubtedly
they might; but as they abound with many acids and strong oils, they
would require a heat more intense than malt does, before they were
sufficiently penetrated, and then the oleaginous parts would become so
compact, and so resinous, as nearly to acquire the consistence of a
varnish, scarcely to be mollified by the hottest water, and hardly ever
to be entirely dissolved by that element.
Barley then ungerminated, either in its natural state or when dried,
is not fit for the purpose of making wines; but when, by germination,
the coarser oils are expelled, and the mealy parts of the grain become
saccharine, might not this suffice, and where is the necessity of the
grain being dried by fire? I shall not dwell on the impossibility of
stopping germination at a proper period, without the assistance of
fire, so that sufficient quantities of the grain, thus prepared, may
always be provided for the purposes of brewing; nor even insist upon
the difficulty of grinding such grain, as, in this case, it would
be spongy and tough. I think it sufficient to mention solely the
unfitness of this imperfect malt, for the purpose it is to be applied
to, that of forming beers and ales capable of preserving themselves
for some time. We should find so many acids blended with the water
still remaining in the grain, that, in the most favorable seasons for
brewing, they would often render all our endeavors abortive, and, in
summer time, make it impracticable to obtain from them sound extracts
in any manner whatever.
I have heard of a project of germinating grain, and drying it by the
heat of the sun, in summer time, in order, by this means, to save the
expence of fuel. Though the hottest days in England may be thought
sufficient for this act, as well as for making hay, yet, as barley
and grass are not of equal densities, the effects would not be the
same. This, however, is not the only objection: as the corn, after a
sufficient germination, should be made inactive, this very hot season,
favorable, in appearance, to one part of the process, would rather
forward, than stop or retard, vegetation; for the barley, by this
heat, would shoot and come forward so fast as to entangle too much the
constituent principles of the grain with one another, and drive the
coarser ill-tasted oils among the finer sweet mealy parts, which alone,
in their utmost purity, are the subject required for such as would
obtain good drinks.
There often appears in mankind a strange disposition to wish for
the gifts of Providence, in a different manner than they have been
allotted to us. The various schemes I have just now mentioned, if I
mistake not, have sprung from the desire of having beers and ales
of the same appearance with white wines. But as they are naturally
more yellow or brown, when brewed from malts dried by heats equal or
superior to that which constitutes them such, all such projects, by
which we endeavour to force some subjects to be of a like color with
others, are but so many attempts against nature, and the prosecution
of them must commonly be attended with disappointments. It is true,
that though the germinated grain be dried slack, yet; if they are
speedily used, and brewed in the most proper season, they may make a
tolerable drink, which will preserve itself sound for some time: but
the proportion, which should be kept between the heat which dried the
malt, and that which is to extract it, cannot, in this case, be truly
ascertained; and, as the grain will be more replete with air, water,
and acids, than it ought to be, the drink, even supposing the most
fortunate success, and that it does not soon turn acid, will still be
frothy, and therefore greatly wanting in salubrity; for an excess in
any of the fermentable principles must always be hurtful.
Barley then, to be made fit for the purpose of brewing, must be malted;
that is, it must be made to sprout or germinate with degrees of heat
nearly equal to those which the seed should be impressed with when
sown in the ground; and it must be dried with a heat superior to
that of vegetation, and capable of checking it. How far germination
should be carried on, we have already seen; the law seems to be fixed
universally, as to the extent of the acrospire: the degree of dryness
admits of a larger latitude, the limits of which shall be the subject
of our next enquiry.
Malt dried in so low a degree, as that the vegetative power is not
entirely destroyed, on laying together in a heap, will generate a
considerable degree of heat, germinate afresh, and send forth its
plume or acrospire quite green. The ultimate parts of the nourishing
principles are then within each other’s power of acting, else this
regermination could not take place; and such grain cannot be said
to be malted, or in a preservative state. Bodies, whose particles
are removed, by heat, beyond their sphere of attraction, can no more
germinate; but, coming in contact with other bodies, as malt with
water, they effervesce. The grain we are now speaking of first shews
this act of effervescence, when it has been thoroughly impressed with
a heat of 120 degrees, and a little before its color, from a white,
begins to incline to the yellow. Such are the malts, which are cured in
a manner to be able to maintain themselves sound, though in this state,
and at this degree of dryness, they possess as much air, and as many
acid and watery particles, as their present denomination can admit of.
This therefore may be termed the first or lowest degree of drying this
grain for malt.
To discover the last or greatest degree of heat it is capable of
enduring, the circumstance to guide us to it, though equally true, is
not so near at hand as effervescence, which helped us to the first. We
must therefore have recourse to the observation of that heat, which
wholly deprives the grain of its principal virtues. Dr. Shaw observes,
_alcohol is one of the most essential parts of wine_; when absent, the
wine loses its nature, and, when properly diffused, it is a certain
remedy for most diseases incident to wines, and keeps them sound and
free from corruption; from whence was derived the method of preserving
vegetable and animal substances.—The same excellent author had before
this observed, that _no subjects but those of the vegetable kingdom
are found to produce this preserving spirit_. Is alcohol, then, a new
body, created by fermentation and distillation; or did it originally,
though latently, reside in the vegetable? _I have for a good while been
satisfied, by experiments_, says Boerhaave, _that all other inflammable
bodies are so only as they contain alcohol in them, or, at least,
something that, on account of its fineness, is exceedingly like it; the
grosser parts thereof, that are left behind, after a separation of this
subtile one, being no longer combustible_.
Now, as the same author has clearly proved[9] that fire, by burning
combustible bodies, as well as by distilling them, separates their
different inflammable principles, according to their various degrees of
subtilty, the alcohol residing in the barley, when exposed to such a
degree of heat as would cause it to boil, i. e. 175 degrees, must make
great efforts to disengage itself from the grain. Is it not, therefore,
natural to conclude, that, in a body like malt, whose parts have been
made to recede from one another, (from whence it is porous, and easily
affected by fire,) prepared for fermentation, or the making a vinous
liquor, this event will probably happen at the same time when the body
of the grain has been ultimately divided by fire, or that malt charrs?
and if this is true, may not charring be termed the last degree of
dryness, when, even somewhat before it takes place, the acid parts and
finest oils, which are necessary for forming a fermentable must, fly
off, and cannot be recovered.—Charring seems to be a crisis in solid
bodies, somewhat analogous to ebullition in fluids; both being thereby
perfectly saturated with fire, their volatile and spiritous parts
tend to fly off. In charring, the subject being ultimately divided by
fire, the constituent principles are set at liberty, and escape in
the atmosphere, in proportion to their several degrees of subtilty,
and to the fire which urged them. In boiling they are equally divided,
and incline to disperse; but, even the more volatile, being surrounded
with water, a medium much denser than themselves, they are caught up
therein, and, by the violent motion caused in boiling, entangled with
it, and with other parts it contains, so as not to be extricated or
divided therefrom except by the act of fermentation. Now, as liquors
boil with a greater or less fire in proportion to their tenacity and
gravity, solid bodies may likewise be charred by various proportions
of heat. The whole body of the barley, as its different parts are of
different texture, cannot, at the same instant, become black, nor,
where any quantity of the grain is under similar circumstances, if not
equally germinated, can the whole charr with the same degree.
To the several reflections, before made, I thought proper to add
the surer help of experience. I therefore made the following trial,
with all the care I was capable of. If the effects of it appear
satisfactory, by gaining two limited and distant degrees, we may
determine and fix the properties of the intermediate spaces, in
proportion to their expansion.
In an earthen pan, of about two feet diameter, and three inches deep,
I put as much of the palest malt, unequally grown, as filled it on a
level to the brim. This I placed over a little charcoal, lighted in a
small stove, and kept continually stirring it from bottom to top.
At first it did not feel so damp as it did about half an hour after. In
about an hour more, it began to look of a bright orange color on the
outside, and appeared more swelled than before. Every one is sensible
that a long-continued custom makes us sufficient judges of colors, and
this sense in a brewer is sufficiently exercised. Then I masticated
some of the grain, and found them to be nearly such as are termed brown
malts. On stirring, and making a heap of them, towards the middle, I
placed therein, at about half depth, the bulb of my thermometer; it
rose to 140 degrees: the malt felt very damp, and had but little smell.
At 165 degrees, I examined it in the same manner as before, and could
perceive no damp; the malt was very brown, and on being chewed, some
few black specks appeared.
Many corns, nearest the bottom, were now become black, and burnt;
I placed my thermometer nearly there, and it rose to 175 degrees:
but, as the particles of fire, ascending from the stove, act on the
thermometer, in proportion to the distance of the situation it is
placed in, through the whole experiment an abatement of five degrees
should be allowed, as near as I could estimate.—Putting, a little
after, my thermometer in the same position, where about half the corns
were black, it shewed 180 degrees. I now judged that the water was
nearly evaporated, and observed the heap grew black apace.
Again, in the centre of the heap, raised in the middle of the pan,
I found the thermometer at 180 degrees; the corn tasted burnt, the
surface appeared, about one half part a full brown, and the rest
black. On being masticated, still some white specks appeared, which
I observed to proceed from those barley-corns which had not been
thoroughly germinated, and whose parts cohering more closely together,
the fire, at this degree, had not penetrated. The thermometer was now
more various, as it was nearer to, or farther from, the bottom; and,
in my opinion, all the true-made malt was charred, for their taste was
insipid, they were brittle, and their skins parting from the kernel.
I, nevertheless, continued the experiment, and, at 190 degrees, still
found some white specks on chewing the grain; the acrospire always
appearing of a deeper black, or brown, than the outward skin; the corn,
at this juncture, fried at the bottom of the pan.
I still increased the fire; and the thermometer, placed in the middle,
between the bottom of the pan, and the upper edge of the corn, shewed
210 degrees. The malt hissed, fried, and smoked abundantly. Though,
during the whole process, the grain had been kept stirring, yet, on
examination, the whole was not equally affected by the fire. A great
part thereof was reduced to perfect cinders, easily crumbling to dust
between the fingers, some of a very black hue, without gloss, some very
black, with oil shining on the outside. Upon the whole, two thirds of
the corn were perfectly black, and the rest of a deep brown, but more
or less so, as the grains were hard, steely, or imperfectly germinated.
This was easily discovered by the length of the shoot: most of the
grains seemed to have lost their cohesion, and had a taste resembling
that of high-roasted coffee.
In the last stage of charring the malt, I placed over it a wine glass
inverted, into which arose a pinguious oily matter, and tasted very
salt. It may, perhaps, not be unnecessary to say, that the length of
time this experiment took up, was four hours, and that the effect it
had, both on myself, and on the person who attended me, was such as
greatly resembled that of inebriation.
Though, from this experiment, the degree of heat at which malt charrs,
is not fixed with the utmost precision, yet we see that black specks
appeared, when the thermometer was at 165 degrees; some of the corns
were entirely black at 175, others at 180. In proportion as fire
causes a deficiency of color, it must occasion a want of fermentable
properties, the whole of which are certainly dispersed, when the grain
becomes of an absolute black. Thus we may conclude, with an exactness
surely sufficient for the purposes of brewing, that true germinated
malts are charred in heats, at about 175 degrees: as these correspond
to the heat at which pure alcohol, or the finest spirit of the grain
itself, boils, it seems to require this heat, wholly to extricate
itself from the more tenacious parts of the corn; which, when deprived
of this etherial enlivening principle, remains inert, incapable of
forming a fermentable must or wort, and indicates to us, that the
constituent parts of vegetables may be resolved by heats, equal to
those between the first degree which formed them, and the last, which
ultimately destroys their properties; though the extracts will possess
different qualities or virtues, according to the determinate heat which
is applied.
SECTION XII.
_OF THE DIFFERENT PROPERTIES OF MALT_,
AND OF THE NUMBER OF ITS FERMENTABLE PARTS.
The consequences resulting from the before-mentioned experiment have
already been hinted at. But it is necessary to trace them farther, and
to shew how much they tend to the information and use of the brewer.
Germinated barleys, so little dried, as that their particles remain
within their sphere of attraction, are not in a preservative state, and
therefore cannot properly be termed malts.
The first degree of dryness, which constitutes them such, as we have
seen before, is that which occasions them to cause some effervescence.
This cannot be effected, when they are dried with less than 120 degrees
of heat; the highest that leaves them white. When urged by a fire of
175 degrees, they are charred, black, and totally void of fermentable
principles. Now this difference of heat, being 55 degrees, and
producing in the grain so great an alteration, as from white to black,
the different shades or colors, belonging to the intermediate degrees,
cannot, with a little practice, be easily mistaken.
White, we know, from Sir Isaac Newton’s experiments, is a composition
of all colors, as black is owing to the absence of them. These two
terms indicate the extremes of the dryness of malt. The color, which
the medium heat impresses upon it, is brown, which, being compounded
of yellow and red, the four tinges which shade malt differently, may
be said to be white, yellow, red and black. The following table,
constructed on these principles, will, on chewing the grain, readily
inform the practitioner of the degree to which his malts have been
dried. It is true some doubts have arisen, whether the increase of heat
is by equal divisions (according to the scales marked on thermometers)
or whether the degrees should not rather be in proportional parts: but
if the effect of fire on bodies (as every experiment shews) is exactly
corresponding to the expansion it is the cause of, this undetermined
question in no wise affects the brewery.
A TABLE _of the different Degrees of the Dryness of Malt, with the
Changes of Color occasioned by each Increase of the Degrees_.
Degrees.
119 White White
124 W. W. Yellow White turning to a light Yellow.
129 W. W. Y. Y. Yellow.
134 W. W. Y. Y. Red, High yellow.
138 W. W. Y. Y. R. R. Amber.
143 W. Y. Y. R. R. Light brown.
148 Y. Y. R. R. Brown.
152 Y. R. R. High brown.
157 Y. R. R. Black, Brown inclining to black.
162 Y. R. R. B. B. High brown, speckled with black.
167 R. R. B. B. Half brown, half black.
171 R. B. B. Coffee color.
176 Black, Black.
N. B. The several letters against each degree, it is apprehended, will
help in practice to fix the color.
The foregoing table not only enables us to judge of the dryness of
the malt by its color, but also, when a grist is composed of several
sorts of malt, to foresee the effect of the whole when blended together
by extraction. Some small error may possibly occur in judgments thus
formed upon the report of our senses; but as malt occupies different
volumes, in proportion to its dryness, if, in the practice of brewing,
upon mixing the water with the malt, the expected degree is observed,
such parcel of malt may be said to have been judged of rightly, in
regard to its dryness. So that the first trial either confirms or
corrects our opinion thereof.
Though malt, dried to 120 degrees, is in a preservative state, yet is
it the least so as malt: it then possesses the whole of its fermentable
principles, which, if not impeded in the extraction, would be very
speedy and active: the duration of the worts to be formed from grain
so low dried, must entirely depend on the power given to the water by
heat, to draw from the malt, oils of such consistence as shall sheath
and retard the hasty effects of the fermentable parts. By extraction,
then, malted grain, even so low dried as this, may, with very hot
waters, and with the farther assistance of hops, be made to produce
beers, which for years will be capable of maintaining themselves sound,
or for a long time to resist the effects of the hottest climates. They
may also, by a less heat being given to the extracting water, and
blended with less hops, form drinks, which shall be fit for use in
so short a time as a week, and perhaps a term much shorter: hence we
see the degree of heat which dried the malt, and the degree of heat
given to the water to extract it. The mean of these numbers (making an
allowance for the quantity of hops used) is that which directs us to
fix the properties and duration of the wort. In one sense, then, we
may consider malt, so low dried as this, as being such as would in the
shortest time furnish us with a fermented liquor, and in another, such
as would yield the most delicate and strongest drink. When malt charrs,
and becomes black, its parts are ultimately divided; it has lost the
principles fit to form a fermentable wort, and which it once possessed.
The degree of heat, prior to that which produces this effect, is the
last which still retains any part of the fermentable properties. In
worts from malt thus highly impressed by fire, fermentation would
proceed with so slow and reluctant a pace, that, in this case, they
might be said to be in the utmost state of preservation. No term
can be fixed for their duration. A liquor of this sort, brewed with
the greatest heat it would admit of, in the extracting water, might
keep many years, and become rather accommodated to the temperature
of the place it was deposited in, than to its own constituent parts.
Experience has shewn, that drinks, impressed by the drying and
extracting heat, with a medium of 148 degrees, with a proper addition
of hops, at the end of eighteen months, have been found sound, and in
a drinkable state; and at this degree we find the middling brown.—From
these two extremes, and on these principles, the following table
is formed, exhibiting the length of time drinks made from malt,
impressed with each respective degree of heat, properly brewed, in the
most favourable season, will require, before they come to their due
perfection to be used.
Equally as with hot extracting waters, low dried pale malt may be made
to yield beers which will long continue in a sound state; so high
dried malt, acted upon by cooler and low extracting water, may be made
to furnish a wort soon fit for use, though less agreeable and more
inelegant. It might here be asked, why, then, at any time, is malt
dried with heats exceeding 120 degrees? In answer to this, it might
justly be said, it would be very difficult for the malster exactly
to hit this point of drying, without deviating from it either on the
one side or on the other; and suppose this difficulty removed, still
he could not be certain every individual grain was equally affected:
if the drying was less than 120 degrees, the malt, by receiving the
moist impressions of the air, would regerminate, and be spoiled. Before
the use of hops, malt was high dried, as a means to keep the extracts
sound. To eradicate an ancient custom or prejudice requires a long
time. This, and the conveniency of keeping malts, was the reason why,
for many years, it was in general dried to excess; an error which
for some time past has been losing ground, as no reason at present
subsists, why malts should exceed in color a light amber.
A TABLE, _shewing the age beers will require, before being used, when
brewed from malts, which, in drying and extracting, have been impressd
with a medium heat corresponding to the following degrees_.
Degrees. Shortest time Longest time Shortest time with the
with 12 lb. with 12 lb. fewest quantity of
of hops. of hops. hops possible.
119 2 Weeks
124 1 Month 3 Months } Brewed { 2 Weeks
129 3 Months 6 Months } in the { 4 Weeks
134 4 Months 9 Months } proper { 6 Weeks
138 6[10] Months 12 Months } season { 6 Weeks
143 7 Months 12 Months } Brewed { 4 Weeks
148 9 Months 12 Months } in { 2 Weeks
} summer {
152 10 Months 18 Months
157 18 Months 2 Years
162 2 Years
167
171
176
It must be observed, that the foregoing table is constructed on the
supposition, that these different sorts of malt are brewed, fermented
with the utmost care, with waters heated to extract it, in proportion
to the dryness of the grain, and to intent of time there set down,
and with an adequate addition of hops; an ingredient which shall be
considered in its proper place. What is meant by the water being heated
to extract malt in proportion to the dryness of the grain, may merit
some explanation.
Grapes, when ripe, carry with them the water they have received, both
during their growing state, and that of their maturity. This quantity
is sufficient to form their musts with. To dried grapes or raisins,
water is added, to supply what they have lost; and for the same reason
it is requisite in regard to malt: but as grapes stand in no need
of artificial fire, to give to their fermentative principles a due
proportion, so what they produce themselves, or cold water applied
to them, when dry, is a sufficient menstruum. But barleys, wanting
the assistance of a great heat to bring their parts to the necessary
proportion, require, when malt, a similar or rather a greater heat to
resolve them: without which, experiment shews, the flour of the grain
would come away undissolved, and thus considerably impoverish the
grist.—Should, on the other hand, too great a heat be applied, an equal
loss would be sustained, from some of the finer parts being coagulated
or blended with oils, tenacious beyond the power of fermentation to
exhibit them. The proportioning therefore the heat of the water to the
dryness of the malt, more especially to obtain from the grain the whole
strength it is capable of yielding, as well as to cause the drink to
preserve itself sound its intended time, is of real necessity.
Well-brewed drinks should not only preserve themselves sound their due
space, in order to be meliorated by time; they should likewise be fine
and transparent.—These circumstances prove the artist’s skill and care,
as well as the salubrity of the drink; and are the surest signs of a
well-formed must, and of a perfect fermentation. If then the rules for
obtaining these ends can be deduced from the foregoing principles and
experiments, we may flatter ourselves with possessing a theory, which
will answer our expectations in practice.
According to the laws of nature discovered by Sir Isaac Newton, the
spaces between the parts of opaque bodies are filled with mediums of
different densities, and the discontinuity of parts, each in themselves
transparent, is the principal cause of their opacity. Salts in powder,
or infused in an improper medium, will intercept the light; gums make
a muddy compound, when joined to spirits; and oils, unassisted by
salts, refuse to be incorporated with water. Musts, therefore, whose
constituent parts are not capable of being dissolved by water into one
homogeneous body, are not fit, either for a perfect fermentation, or a
pellucid drink.
Length of time, which improves beers and wines, often rectifies our
errors in this respect; for the oils being, by various frettings,
more attenuated, and more intimately mixed, the liquor is frequently
restored, and becomes of itself pellucid. Yet I never found this to
succeed, where the error upon the whole of the dryness of the malt, and
the heat of the extracts, exceeded the medium by 10 degrees.
Art has also, in some measure, concurred with nature to remedy this
defect. When beers or wines have been suffered to stand, till they are
rather in an attracting than in a repelling state, that is, when their
fermentations and frettings apparently stand still; then, if they do
not become spontaneously fine, they may be precipitated, by mixing with
them a more ponderous fluid. The floating particles, that occasioned
the foulness, are, by this means, made to subside to the bottom,
and leave a limpid wine: but the power of dissolved isinglass, the
ingredient generally used for this purpose, seldom takes effect, when
the error exceeds the medium, as before, by more than 10 degrees.
Other ingredients, indeed, have been used, which carry this power
near 10 degrees farther. It is not my province to determine, whether
such be salutary: undoubtedly it would be better if there were no
occasion for them. Beyond these limits, precipitation has no effect;
the liquor, which cannot be fined thereby, if attempted, by increasing
the quantity of the precipitants, will be overpowered by the menstruum,
and injured in its taste. How frequent this last case of cloudiness is,
would answer no purpose in this place to enquire. The use of doubtful
ingredients, and such errors as have been mentioned, need no longer
blemish the art, when a constant and happy practice, will be both the
effect and the proof of a solid and experimental theory.
Beers which become bright of themselves, or by time alone, as well as
those precipitated either by dissolved isinglass, or by more powerful
means, each possess their respective properties in a certain latitude
or number of degrees; and as these effects arise wholly from the
heats employed in drying the malts, and in forming the extracts, the
following table will be of use to point out the limits, within which
each drink may be obtained.
A TABLE, _shewing the tendency beers have to become fine, when the
malt, in drying and extracting, has been impressed with heats, the
medium of which answers to the following degrees, supposed to be brewed
and kept in the most eligible manner_.
Deg.
119 White, } Immediately. } Latitude of
124 Inclining to yellow, } } musts which
} fine
129 Yellow, 2 Months. } spontaneously.
134 High yellow, 4 Months. }
138 Amber, 6 Months. } Latitude of
143 Light brown, 8 Months. } musts which
148 Brown, 10 Months. } fine by precipitation.
152 High brown, 12 Months. }
157 { Brown, inclining to } 14 Months. } Latitude of
{ black, } } heats which
} cannot form
162 { High brown speckled } 16 Months. } musts, so as
{ with black, } to answer
} the intent
167 { Half brown half 18 Months. } of becoming
{ black, } wholesome
171 Coffee color, } 20 Months. } beer.
176 Black, } }
The difference between the heat for forming grapes, and the greatest
heat which ripened them, affords to us the number of degrees answerable
to their constituent parts: the investigation of barley, in like
manner, though less important to our purpose, yet may, with some
propriety, be admitted.
Upon examination it will be found, barley ears, and the new grain
begins to form (being still in possession of its flower) about the same
time with us as grapes do, in June; when we found the mean heat of the
air in the shade to be 57.60 degrees.
Barleys in general are mowed from August to September; so that, in
their growth, they are benefited by the whole of our summer’s heat, and
for like reasons as in page 59, we estimate this 61.10 degrees: 3.50
degrees then would be the number of their constituent parts, taken from
the degrees of heat in the shade, and which perhaps would be different
if the actual sun-shine heat and what is reflected from the earth,
were accounted for. Barleys are annuals, unbenefited by the whole of
the autumn sun; but, after being mowed, they are stacked, retaining
still much of their straw, leaves, and outward skins. In these heaps
they heat, more or less, according to the condition in which they were
housed; and which heat may reach to 120 degrees or more, but in general
is equal, or somewhat superior, to that of our bodies. The properties
of the grain, by this means improved, ripen, and from hence are more
capable of preserving themselves. This might be a reason why a farther
allowance should be made to the number of degrees denoting their
constituent parts: how much, by a very great number of observations,
made from the germination, ripening, to the stacking of the barley, in
many years, and in many cases, might probably be ascertained; but the
difficulty of doing this, and afterwards the impossibility of complying
with the information such enquiries would afford, and the little need
there is for it, as nature has allowed a considerable latitude for our
deviating from what may be styled perfection, without any sensible
injury: these circumstances render such enquiries unnecessary, if not
fruitless.
Vegetables, but more particularly barley, from their first origin to
such time as they might be ultimately separated by fire, may be divided
into different periods, according to the distinct properties belonging
to each, (and each of these require again a more exact enquiry.)
Barley is under the act of germination, so long as the acrospire or
stem is within the outward skin of the parent corn; this excluded,
it vegetates so long as it receives nourishment by the interposition
of its roots. It may be said to be in a state of concentration, when
receiving but little or no support from the earth, yet it is acted upon
by such heats as do not exceed what it might bear in the vegetative
period; and in that of inaction, when, by the power of heat, it is
placed in a passive state. Now malt is barley germinated, and, by a
quick transition, is impressed with heats superior to those admitted
in vegetation, and such as places the corn in a state of inaction.
In the beginning of the process of malting, the more tenacious oils,
together with some salts, are excluded from the body of the grain, to
form the vessels requisite to forward the growth of the future plant.
What remains in the parent grain (that choice food, at first necessary
to the infant barley) are saccharine salts, alone applicable to the
brewer’s purpose, and of the nature and quantity of which, he ought
to be well acquainted. To retain these, and prevent a waste thereof,
the germinated corn is placed in such heat, as destroys the union
between its parts, from whence it becomes inactive. When this intent is
obtained by the least heat capable of effecting it, the malt retains
both its color, and the whole of its properties.
Vegetables, in no part of their growth, are ever affected by heats
so great as to disperse their constituent parts; on the contrary,
by natural heats, in general they are improved. The whole of their
elements then, must be measured from the first degrees which form
them, to the last which procure their highest perfection; and in
climates where they are not benefited by the whole of such heat, their
properties must be accounted only so many degrees, as in such places
are between the extremes of their germination and maturation. Alike
with malt, their whole number of constituent parts, denoted by degrees
of heat, must be so many as are comprehended between that degree which
leaves it in possession of the whole of their elements, and the first
heat which excludes a part; for malt more dried than this, being less
perfect, and losing some of its properties, fewer must remain.
The degree of heat which in malt divides the period of germination from
that of inaction, we have found to be 119; the grain then is perfectly
white, and shews little if any sign of effervescence; the first change,
fire occasions therein, is to impress it with a light yellow color;
this takes place at 129 degrees of heat, an alteration which can
proceed from no other cause, but, in removing its original whiteness,
to have expelled some of its primitive parts. The difference then
between these two numbers of 10, specifies, in degrees of Fahrenheit’s
scale, the number of properties constituting barley, malt.
It must be confessed this is establishing a principle of the art of
brewing, upon the uncertain report of our senses, as perhaps our
sight may deceive us in fixing this change of color exactly at 129
degrees; but we know white and black to be the two extremes of the
dryness of malt, and that the middle color between them is brown,
which being compounded of yellow and red, these four tinges, equally
divided, as we have done in the foregoing tables, will corroborate
our fixing the teint of yellow at this degree. The table shewing the
tendency beers have to become fine, was formed from experiments made
on brewings, whose governing medium heats were from 134 to 148, the
proportion in point of time given by these, justifies the division
between immediate pellucidity, at 119, and that taking place at two
months, or 129 degrees. So from hence we may be satisfied, however an
absolute perfection cannot be depended upon, yet this being the most
exact division our senses afford, it approaches so near to truth,
that if any mistake remains, it can be but trivial, compared to the
latitude of errors, fermentation and time correct. But this number,
10 degrees, denoting the quantity of fermentable parts, must lessen
in proportion as a continued, or a greater heat deprives the grain of
more properties. A speedy spontaneous pellucidity is the effect of
the whole fermentable parts; malt affected by heat, conveyed either
through air or water, or through both, (so the medium of these exceeds
not 138 degrees,) if assisted by the acids gained to the drink by
long standing, such will obtain transparency. Beers, then, intended
to be formed of themselves to become fine, in the calculations used
to discover their elements, so many of the members of the constituent
parts must be implied, as corresponds with the time the beer is
intended to be kept; but when beers are made intentionally to require
precipitation to become fine, in such proportion as we purpose to
impress opacity on the drink, we must, in the calculations made to
discover the temperature of the extracts, imply only so many of the
constituent parts, as correspond to the medium heat which will
occasion this foulness. These few observations shew the necessity of
establishing this fundamental doctrine, the use of which will obviously
appear in practice.
Thus does the success of this art depend on the instrument so often
mentioned, which, by indicating the expansions caused by different
heats, becomes a sure guide in our operations. I shall now close this
account, by comparing with the principles here laid down, the defects
which we, but too often, meet in barley when malted.
SECTION XIII.
_OBSERVATIONS ON DEFECTIVE MALTS._
In the preceding enquiry, some of the defects of malt have been
occasionally mentioned: but as a perfect knowledge of the grain,
especially when it has undergone this process, is a matter of no small
concern to the brewer, I shall now bring such defects into distinct
view, both to compare them with the foregoing principles, and that the
knowledge of them may be more at hand, on every occasion, when wanted.
Every different degree of heat acting on bodies causes a different
effect: and this varies also, as such heat is more or less hastily
applied. The growth of vegetables is in general submitted to these
laws: but yet I conceive there is some difference between germination
and vegetation, which I beg leave to point out. The former seems to
be the act caused by heat and moisture, while the plume or acrospire
is still enveloped within the teguments of the parent corn, and it is
most perfectly performed by the gentlest action, and consequently by
the least heat, that is capable of moving the different principles in
their due order. Vegetation, again, is that act which takes place when
the plant issues forth, and, being rendered stronger by the impressions
of the air, becomes capable of resisting its inclemencies, or the
warmth of the sun-shine. Germination is the only act necessary for
malting, the intention being solely to put in motion the principles
of the grain, and not to rear up the embryo to a plant. Now, as this
begins in barley at the degree where the water first becomes fluid,
or nearly so, the cold season, when the thermometer shews from about
32 to 40 degrees, would seem the most proper for this purpose. How
far its latitude may with propriety be extended, experience alone can
determine. Maltsters continue to work so long as they think the season
permits, and leave off generally in May, when the heat of the water
extends at a medium from 50 to 55 degrees. But the nearer they come
to this medium, with the greater disadvantage must they malt: as, by
such warmth, the vessels of the corn are much distended, the motion
of the fluids violent, and the finer parts too apt to fly off. Thus
the coarser oils gaining admittance, the glandular parts become filled
with an impure and less delicate sulphur, which, instead of a sweet,
inclines to a bitter, taste. This is so manifest, and so universally
experienced, that, in general, brewers carefully avoid purchasing what
is termed _latter-made malts_.
Malt, which has not had a sufficient time to shoot, so that its plume
may have reached to the extent of the inward skin of the barley,
remains overburthened with too large a quantity of earth and oils,
which otherwise would have been expended in the acrospire and radical
vessels. All those parts of the corn which have not been separated, and
put in motion by the act of germination, will, when laid on the kiln to
dry, harden and glutinize: no greater part thereof will be soluble in
water, than so far as the stem or spire of the barley rises to, or very
little farther, and as much as is wanting thereof will be lost to the
strength of the drink.
When malt is suffered to grow too much, or until the spire is shot
through the skin of the barley, which is not often the case, though all
that is left be malt, that is, containing salts dissoluble in water,
yet as too large a portion of oils has been expended out of the grain,
such malts cannot be fit to brew drinks for long keeping.—There is,
besides, a real loss of the substance of the corn, occasioned by its
being overgrown.
Malt, the germination of which has reached and been stopped at the
proper period, and has been duly worked upon the floors, if not
sufficiently dried on the kiln, even though the fire be excited to a
proper heat, retains many watery parts. The corn, when laid together,
will be apt to germinate afresh, perhaps to heat so as to take fire;
should not this extreme be the case, at least it must grow mouldy, and
communicate an ill flavor to the drink.
Malt, well grown, and worked as before, but over-dried, though with
a proper degree of heat, will become of so tenacious a nature, as to
require a long time before it can admit of the outward impressions of
the air to relax or mellow it, that is, before it is fit to be brewed
with all the advantages it otherwise would have; and in proportion
as it has black specks on being masticated, so much of its parts
being charred is a diminution to the strength of the liquor, besides
impressing it with a burnt or nauseous taste.
Malt, dried on a kiln not sufficiently heated, must require
proportionably a longer time to receive the proper effect of the
fire; the want of which will bring it into the same state as malt not
thoroughly dried.
If too quick or fierce a fire be employed, instead of gently
evaporating the watery parts of the corn, it torrifies the outward
skin, divides it from the body of the grain, and so rarifies the
inclosed air as to burst the vessels. Such is called _blown malt_, and,
by the internal expansion, occupies a larger space than it ought. If
the fire be continued, it causes its constituent parts to harden to the
consistence of a varnish, or changes it into a brittle substance, from
whence the malt is said to be steely and glassy: it dissolves but in
a small proportion, is very troublesome and dangerous in brewing, and
frequently occasions a total want of extraction; by the brewery termed,
_setting the grist_.
Malt, just, or but lately, taken from the kiln, remains warm for
a considerable time. Until the heap becomes equally cool with the
surrounding air, it cannot be said to be mellow, or in a fit state
to be brewed: its parts being harsh and brittle, the whole of its
substance cannot be resolved, and the proper heat of the water, which
should be applied to it for that purpose, is therefore more difficult
to be ascertained.
The practice of those maltsters, who sprinkle water on malt newly
removed from the kiln, to make it appear as having been made a long
space of time, or, as they say, to _plump_ it, is a deceit which cannot
too much be exposed. By this practice, the circumstance of the heat,
and harshness of the malt, is only externally, and in appearance,
removed, and the purchaser grossly imposed on. The grain, by being
moistened, occupies a greater volume, and, if not speedily used, soon
grows mouldy, heats, and is greatly damaged.
The direct contrary is the case of malt which has been made a long
time: the dampness of the air has relaxed it, and so much moisture
has insinuated itself into the grain, that some doubt must arise how
much hotter the mash should, for this reason, be. Yet, supposing no
distemper, such as being mouldy, heated, or damaged by vermin, it is
observed, malt, under this circumstance, may more certainly be helped
in brewing, than those just abovementioned.
From what has been said, it appears how necessary it is to procure
malt which has been properly steeped, germinated to its true pitch,
and dried by a gentle, moderate heat, so as the moisture of the corn
be duly evaporated, then cured by just so much fire as to enable it
to preserve itself a due time, without being blown or burnt. How easy
it is to regulate this process in the cistern, in the couch, on the
floors, and on the kiln, when the malster, intends no artifice to save
his excise, I need not say; but with what certainty and ease the whole
might be carried on by the help of the thermometer, I leave such to
determine as are modest enough to think, that the art may be brought
to more accurate rules than those of the bare report of our unassisted
senses. As such rules may easily be deduced from the principles here
laid down, I shall not be more particular in shewing their application,
as not being my immediate purpose, nor my business as a brewer: nor
have I leisure, or the conveniency of a malt house, to make experiments
of this sort; yet with truth it may be said, that such as would not
be disappointed in their brewing, must take care not to be deceived
in their malt. This, however, being but too frequently the case, we
should constantly be on our guard against its defects, and know how to
correct them. If it is treated in the same manner as if it was perfect,
the well-malted parts alone will be digested. If too slack dried, it
may be corrected by an addition of heat, if over-dried, or injured by
fire, it may proportionably be helped. By applying the thermometer to
the extracts, more particularly to the first, the brewer thereby will
be informed, to a sufficient degree of exactness, of the defects he can
mend, and hardly be ever at a loss for the properest means to work the
grain to the greatest advantage.
As far as we have proceeded in our enquiry, though some satisfaction
must arise from our being enabled to account for the greater part
of the process of brewing, yet it may be observed, even with the
assistance of the thermometer, as yet a geometrical exactness, in
many respects, has not been attained; but nature, when the interest
and necessities of mankind are the object, apparently has supplied
our wants, and rectified our defects. In this art, fermentation, when
allowed to display itself, corrects all our errors to a considerable
latitude, though as yet, of this act, it may be said we scarcely
conceive its cause, or properly discern its effects.
PART II.
THE
PRACTICE OF BREWING.
Before I enter upon the practical, and indeed most important, part of
this work, it will not be improper to give a distinct, though general,
view of the different parts it is to consist of.
To extract from malt a liquor, which, by the help of fermentation, may
acquire the properties of wine, is the general object of the brewer,
and the rules of that art are the subject of these sheets.
An art truly very simple, if, according to vulgar opinion, it consisted
in nothing else than applying warm-water to malt, mashing these
together, multiplying the taps at discretion, boiling the extracts
with a few hops, suffering the worts to cool, adding yeast to make it
ferment, and trusting to time, cellars, and nostrums, for its taste,
brightness, and preservation!
A few notes and observations, such as are too often found to be foisted
under the articles of beer and brewing, in some books of agriculture
and others of cookery, might be sufficient, were the place and
constitution of the air always the same, the materials and vessels
employed entirely similar, and lastly, the malt drinks intended for the
same use and time; but, as every one of these particulars is liable
to variations, and can be complied with, only by the application of
different determinate heats; was the artist to submit himself to loose,
vague, and erroneous directions, like those above mentioned, they would
only serve to deceive him, and his case would be but little mended,
if he trusted to indefinite signs, and insufficient maxims, in his
deviation from them.
A more certain foundation has been laid down in the first part of this
treatise, and the principles there established will, I trust, in all
cases, answer our ends, provided we make use of proper means to settle
their application. The most elegible means to effect this, must be
to follow, as near as possible, such plan, which the rational brewer
would, in every particular circumstance, sketch to himself, before he
proceeded to business. His first attention ought to be directed not
only to the actual heat of the weather, but also to that which may be
expected in the season of the year he is in. The grinding of his malt
must be his next object, and as the difference of the drinks greatly
depends upon that of the extracts, he cannot but chuse to have distinct
ideas of what may be expected from the amount of the heat of them.
Hops, which are added as a preservative to the extracts form too
important a part to be employed without a sufficient knowledge of their
power. The strength of malt liquors depending principally on their
quantity or lengths, it is necessary to ascertain the heights in the
copper, to answer what, on this account, is intended. The difference
in boiling, for different drinks or seasons; the loss of water by
evaporation; the proper division of the whole quantity of this element
employed, and, in proportion to such division, that of the heat to
be given in each part of the process; the means to ascertain these
degrees, by determining what quantity of cold water is to be added
to that, which is at the point of ebullition, come afterwards under
his consideration. The manner and time of mashing, the many expected
incidents which must produce some small variations between the actual
and the calculated heat of his extracts, it will be incumbent upon
him to make a proper estimation and allowance for. To dispose of the
worts in such forms and at such depths, as may render the influence
of the ambient air the easiest and most efficacious, and then, by
the addition of yeast, to provide the drink with that internal and
most powerful agent it had lost in boiling, are the next requisites.
Fermentation, which follows, and which the brewer retards or forwards
according to his intentions, completes the whole process; after these
necessary precautions, to compare his operations with those of the
most approved practitioners in his art, and to find himself able to
account for those signs and established customs, which before were
loosely described, authoritatively dictated, and never sufficiently
determined or explained, must be to him an additional satisfaction. As
precipitation is requisite in certain cases, the common methods for
effecting it should be known, and likewise the means practised among
coopers to correct the real or imagined errors of the brewer, in order
to render the drink agreeable to the palate of the consumers, will
naturally lead him to consider what true taste is, and by employing
the means, by which it may safely be obtained and improved, he will
have done all in his power, to answer his customers expectation, and to
secure his success.
This arrangement, which appears the most simple, is that, which the
reader will find observed in the following sections. The proper
illustrations of tables and examples have not been omitted, and from
the complete plans for brewing, under two forms of the most dissimilar
kind, it will be found the rules are adapted to all circumstances, and
applicable to every purpose.
I must here add somewhat in justification, for publishing what may be
said to be the mysteries of an art, often too cautiously precluded
from the sight and attention of the public; but every art and science
whatever have equally been laid open, and from such communication
received greater improvements, and become more useful to mankind in
general, and the professors of them in particular. If attention is
given to the rules and practice here laid down, it will be found that
the brewer, from the large quantities he manufactures, from repeated
experience, from the conveniency of his utensils, and more than all,
from the interest he has to be well acquainted with his business,
is most likely to be successful, in preference to any one else, and
therefore can have no reason to be displeased on being presented with
a theory and practice, which, far from being the sole right of the
brewery, the discovery of the principles were certainly the property of
the author and of his friends, whose names would do his work honor if
mentioned. From the application of these principles, being convinced
of their exactness and facility in practice, he offers his labor to a
trade he esteems, with no other view than the hope he entertains of
being of some service to it and to the public.
If, notwithstanding repeated endeavours, some things, in this
treatise, should appear out of their places; others, in more than
one; if redundancies, chiefly occasioned by the natural temptation of
accounting for particular appearances, have not always been avoided; if
inaccuracies should now and then have escaped me, let it be remembered
(by the good-natured it certainly will) that, in new and intricate
subjects, digressions and repetitions are in some measure allowable,
that an over-fulness is preferable to an affected and often obscure
brevity, and that the improvement of the art, rather than the talent of
writing, must be the brewer’s merit, and was my only aim.
SECTION I.
_OF THE HEAT OF THE AIR_,
AS IT RELATES TO THE PRACTICAL PART OF BREWING.
In and about the city of London, the most intense cold that has been
observed is 14 degrees, and the greatest heat has made the thermometer
rise, in the shade, to 89. Within these limits are comprehended all the
fermentable degrees, and consequently those necessary for carrying on
the process of brewing. If the lowest degree proper for fermentation
be 40, and the highest 80, the medium of these two would, at first
sight, appear to be the fittest for this purpose; but the internal
motion, necessary to carry on fermentation, excites a heat superior to
the original state of the must by 10 degrees. Hence, if 60 degrees be
the highest eligible heat a fermenting must should arise to, 50 should
be the highest for a wort to be let down at, to begin this act; which
heat can only be obtained, when that of the air is equal thereto, so
that it denotes the highest natural heat for beers and ales to be
properly fermented. With regard to the other extreme, or the lowest
heat, however cold the air may be, as the worts, which form both beers
and ales, gain, by boiling, a degree greatly superior to any allowed
of in fermentation, it is constantly in the artist’s power to adapt
his worts to a proper state. The brewing season, then, may justly be
esteemed all that part of the year in which the medium heat of the day
is at or below 50 degrees: this, in our climate, is from the beginning
of October to the middle of May, or 32 weeks; the most elegible period
of time for brewing all kinds of beers.
But, as many incidents often make it necessary to extend these limits,
the only time for venturing to comply therewith is, when the medium
heat of the season is at 55 degrees; by which, six weeks more may be
obtained. But, under these circumstances, the quantity of beer brewed
should be less, that the worts may cool more readily, by being thinner
spread; and, to gain more time, the brewing is best carried on with
two worts only: taking these precautions, and beginning early in the
morning, the first wort, by laying long enough in the coolers, will,
towards evening, be brought to a heat of 55 degrees. The night, in this
season of the year, being generally colder by 10 or 12 degrees than the
medium heat of the whole 24 hours, the second worts may be reduced to a
cold of 43 degrees: the mean of 55 and 43, being 49 degrees, would be
the real heat of the worts in the ton; and with 10 degrees more, (the
heat gained by fermentation,) still it would not reach 60 degrees, the
highest fermentable heat, beers intended to preserve themselves long
should arrive to; but so near would it be to this, and so little is
the uniformity of the heat of the air to be relied on, that necessity
alone can justify the practice of brewing such drinks, when the heat
of the air is so high as 55, consequently, where it exceeds this, it
should never be attempted.
As the extractions are made by heats far superior to any natural
ones, though the actual temperature of the air neither adds to,
nor diminishes from, their strength, yet it is to be known for the
following reason. The proper heat given to the mash is by means of cold
added to boiling water; and cold water generally is of no other heat
than that of the air itself. Indeed, when the cold is so intense, as to
occasion a frost, and to change water into ice, that which is then used
for brewing, being mostly drawn from deep wells, or places where frost
never, or but seldom, takes place, may be estimated at 35 degrees, and
this will be sufficiently exact.
The following table shews the temperature of the air for every season
in the year, and confirms what I have just now said concerning the
season proper for brewing, and the actual heat of the water. It
was deduced from many years’ observations, made with very accurate
instruments, at eight o’clock in the morning, the time in which the
heat is supposed to be the medium of that of the whole day.
A table, _shewing the medium heat, for every Season of the year, in
and about London, deduced from observations made from 1753 to 1765, at
eight o’clock each morning_.
Degrees.
January 1 } 36′ 38 July 1 } 60′ 52
to 15 } to 15 }
to 31 } 34′ 97 to 31 } 60′ 29
February 1 } 35′ 51 August 1 } 59′ 89
to 14 } to 15 }
to 28 } 38′ 11 to 31 } 58′ 48
March 1 } 37′ 99 Septemb. 1 } 55′ 17
to 15 } to 15 }
to 31 } 39′ 72 to 30 } 54′ 13
April 1 } 43′ 13 October 1 } 48′ 66
to 15 } to 15 }
to 30 } 46′ 04 to 31 } 46′ 72
May 1 } 49′ 05 Novemb. 1 } 42′ 26
to 15 } to 15 }
to 31 } 53′ 67 to 30 } 39′ 40
June 1 } 57′ 20 Decemb. 1 } 38′ 61
to 15 } to 15 }
to 30 } 59′ 14 to 31 } 37′ 54
To ascertain the authority of this table, and to make it useful to
several purposes, I have carried to decimals the mean numbers resulting
from my observations.—But such an exactness has been found, in the
practice of brewing, to be more troublesome than necessary. I have
therefore constructed another table, similar to the former, but where
the fractions are omitted, and the whole numbers carried on from five
to five. The heats of the latter end of October, and beginning of
November, have here been set down rather higher than they really are;
as, at this time of the year, the hops fit to brew with are old and
weak, and I could not devise any means more easy to allow for their
want of strength.
A TABLE, _shewing the medium heat of the air, in and about London, for
every season of the year, applicable to practice_.
Degrees. Degrees.
January 1 } July 1 }
to 15 } 35 to 15 } 60
to 31 } 35 to 31 } 60
February 1 } August 1 }
to 14 } 35 to 15 } 60
to 28 } 40 to 31 } 60
March 1 } Septemb. 1 }
to 15 } 40 to 15 } 55
to 31 } 40 to 30 } 55
April 1 } October 1 }
to 15 } 45 to 15 } 50
to 30 } 45 to 31 } 50
May 1 } Novemb. 1 }
to 15 } 50 to 15 } 45
to 31 } 50 to 30 } 40
June 1 } December 1 }
to 15 } 60 to 15 } 40
to 30 } 60 to 31 } 35
As nothing is so inconstant as the heat of the air, we are not to
be surprised when it deviates from the progression specified in the
table. The flowing water used in the brewery, at the coldest seasons,
we have fixed at 35 degrees, and the highest heat in the air, to carry
on the process for beers brewed for long keeping, at 55 degrees. The
length proper to be drawn, or the quantity of beer to be made from each
quarter of malt being fixed, the brewer, at any time, has it in his
power to make calculations for brewings, supposing the mean heat of the
air to be at 35, at 40, at 45, at 50 and even at any degree of heat
whatever, so as never to be unprovided for any season. Water, being a
body more dense than air, requires some time to receive the impressions
either of heat or cold, for which reason the medium heat of the shade
of the preceding day, will most conveniently govern this part of the
process, unless some very extraordinary change should happen in the
atmosphere. This must make the business of the artist, in this respect,
very easy, as, in the course of his practice, he will have only to
correct the little changes that occasional incidents give rise to; and
the calculations will answer all his purposes so long as the lengths of
beer to be brewed from the same quantity of malt remain unaltered, and
with very little variation and trouble, when the coppers employed, by
being changed, are of different dimensions.
The best method to know the true heat of cold water, would be to
keep a very accurate and distinct thermometer, in the liquor back;
but as this, in every place, is not to be expected, and inaccuracies
must arise from a change in the air, to prevent their consequences in
practice, we must have recourse to experience. This has taught us that
a difference of 8 degrees, between the actual heat of the water, and
that from which the brewing was computed, will produce, in the first
extract, a difference of four degrees.
Most brewers’ coppers, though they vary in their dimensions, are
generally made in proportions nearly uniform; the effect of one inch
of cold water more or less, will therefore nearly answer alike, that
is, it will alter the heat of the tap, by 4 degrees. But this will only
hold good in such cases, where the water is in the same proportion to
the volume of the grist. In brewing brown beers, or porter, three worts
are generally made; the extracts therefore must be of different lengths
from what they are in beers brewed at two worts only. In this case, the
quantity of water for the first wort, is less than it otherwise would
be; and what must be allowed for the first mash, to wet the malt, is so
much as to occasion the second, or piece liquor, to be proportionably
less also; as it is of great consequence, if the first tap doth not
answer to its proper degree, that the second should be brought to such
a heat, as to make up the medium of the first and second extracts,
the second, or piece liquor, by reason of its shortness, is more
conveniently, and more exactly tempered in the little copper; and
one inch cooling in, is in this case found, both by calculation and
experience, to occasion a difference of one degree of heat only in the
mash.
One of the principal attentions, in forming beers and ales of any sort
whatever, is that they may come to their most perfect state, at the
time they are intended to be used. Common small beer is required to be
in order, from one to four weeks, and as it is impossible to prejudge
the accidental variations, as to heat and cold, that may happen in
any one season of the year, it is rational to act up to what a long
experience has shown, is to be expected, and to mix such quantity of
cold water with that, which is made to come to ebullition, as to bring
the extract to the degree fixed for each particular season, let the
heat, at the time of brewing, vary therefrom, in any degree whatever.
In treating on the subject of air, in the former part of this work, I
observed the effect it had in penetrating the parts of the malt, or
in the technical term used by brewers, in slacking it. As such is the
case, when the grain is entire and whole, it is more so when ground,
and experience teaches us, that, when malt has been about 24 hours from
the mill, the dampness it has imbibed is equal to half an inch more
of cold water added to that which is to be made to boil for the first
liquor, and produces therefore a diminution of 4 degrees in the heat
of the tap[11].
An effect, somewhat resembling this, is caused by the impression of
the air on the utensils of a brewhouse, which are not daily used;
the heat received from a foregoing process has expanded their pores,
and rendered them more susceptible of cold and moisture. From this
circumstance, the heat of the first mash will be affected in a
proportion equal to half an inch less cooling in, or in the space of 24
hours, to 4 degrees of heat.
The time of the day, in which the first extract is made, becomes
another consideration; for as 8 o’clock in the morning is the time
of the medium heat in the whole 24 hours, the other hours will give
different degrees. When a first mash is made about 4 o’clock in the
morning, the following table shews the difference between the heat at
4 and 8; that of the other hours, in the like case, may be learned by
observation. It has been observed, that, in the cold months, from the
sun’s power being less, the heat of the day and night are more uniform,
and also that the coldest part of the 24 hours is about half an hour,
or an hour before sun-rising. I have judged it convenient to place, in
the same table, the several incidents affecting the first extract.
INCIDENTS _occasioned by the air affecting the heat of the
first extract, to be noticed more particularly, when small beer is
brewed, as the quantity of water is then greatest, and the mash more
susceptible of its impressions_.
Morning at 4 o’clock*
January 0 Utensils, for want of being
used, in 24 hours
February 0 lose 4 degrees of heat,
equal to half an inch of
March. 2 cold water.
Malt, which has been
April 4 ground 24 hours, imbibes
moisture equivalent
May 6 to half an inch,
which lessens the heat
June 8 by 4 degrees.
The difference between
July 10 the actual heat of the
air, and that naturally
August 8 expected is to be allowed
in proportion of
September 6 8 degrees to one inch
cooling in.
October 4 Malts, from having been
long kept, or old,
November 2 become considerably
slacked.
December 0
* Colder by so many degrees than at
eight o’clock in the morning.
Before we quit this subject, it may not be improper to observe,
that, in the hottest season, and in the hottest part of the day, the
difference between the heat of the air in the shade, and that in the
sun’s beams in and about London, is nearly 16 degrees, and also that
cellars or repositories for beers, are, in winter, generally hotter by
ten degrees, than the external air; and in summer, colder, by five.