to alter the spontaneous course of nature; yet if, by the assistance of
the instruments, and means recommended, we are enabled to foresee and
provide for the changes induced by the alterations of the atmosphere,
we can guard against the inconveniences in some cases, and make them
subservient to our purpose in others; so as more securely to conduct
the process in each to advantage; and that with unusual facility;
complex as it at present appears: it will not only be a great
improvement in the present mode of fermentation; but facilitate our
progress to still greater improvements in the doctrine of fermentation.
Therefore, the rule of our conduct, in these pursuits, should be to
watch the operations of nature with the closest attention, and assist
her when languid, and control her when too violent; that is, by
spurring in one instance, and bridling in the other, and accurately and
undeviatingly apply the means proposed in the manner recommended, until
experience enables us to improve it; otherwise, we shall only admire,
without improving or profiting by her choicest phenomena.
The motions of the planets, perplexed and intricate as they must have
appeared in the infancy of astronomy, are now calculated and known with
ease and precision.
Attenuation is a term not unaptly applied to fermentation, the property
of attenuation being to divide, then dilute, and rarify thick, gross,
viscid, and dense substances, in which some degree of fluidity is
pre-supposed; it is, therefore, that kind of dilution or fluidity which
is promoted by agitation, and very aptly applied to mark the progress
of fermentation, which is itself the process of nature, for decomposing
vegetable and animal substances under a convenient degree of fluidity;
it exists in intestine motion, either spontaneous or excited,
accompanied with heat, which, under certain limits, is proportioned to
the vigour of the fermentation, which ends in the decomposition of one
class of bodies, and the composition of another; and which may be
instanced in the resolving saccharine substances into hydrogen, oxygen,
and carbon, and the combining them into inflammable spirits, or
alcohol, and inflammable acids or vinegar; to which may be added, the
lower you attenuate, the lighter and more spiritous the fermenting
fluid becomes; and that attenuation, which is the offspring of
fermentation, like the parent process, has its bounds, and can only be
conducted with certainty and advantage by the use of the hydrometer,
thermometer, &c. In this only lies the difference between the old word
fermentation, and the new word attenuation, every thing used as a
ferment, or to promote fermentation, is attenuant. The tendency of the
vinous process of fermentation is to evolve or disentangle the hydrogen
of the fermenting fluid, and unite it, with the carbon and oxygen of
the same fluid, into ardent spirit, wine, beer, or alcohol, which last
is well known to be inflammable. The tendency of the acetous process of
fermentation, is to involve or entangle the hydrogen and carbon of the
fermented fluid, with a greater proportion of oxygen, into vinegar,
which is uninflammable. The fixed air, or carbonic acid gas, so
abundantly extricated during the vinous process of fermentation, which
every one concerned in the process is presumed to be acquainted with,
is either composed of hydrogen and oxygen, or is a composition of
carbon and oxygen, on which philosophers are divided in opinion. As the
result is the same with respect to the formation of wine, beer, and
spirit, I shall enter into no controversial reasoning on this head,
instead of which, I shall endeavour to point out the most effectual
mode of saving and profitably applying it, and the other elements, in
the composition of wine, beer, spirit, and acid.
As in fermentation, spontaneous or excited, there is a sensible escape
of carbonic acid gas, or fixed air, it may not be improper to note,
that fermentable, or saccharine matter, consists of about twenty-eight
pounds of carbon, eight pounds of hydrogen, and sixty-four pounds of
oxygen, reducible into fixed, inflammable, and vital air, weighing one
hundred subtile pounds in toto, or that every one hundred subtile
pounds of saccharine matter consists of such proportions of these airs
and gasses.
Attenuation is the result of a due resolution of the fermentable matter
produced by excited fermentation, which divides mucilages, resolves
viscidities, breaks down cohesions, generates heat and motion,
extricates the imprisoned gasses, and, by frequent commixture, promotes
the action and re-action of the component particles on each other, and
by continually exposing a fresh surface and opposition of matter,
brings them within the sphere of each other's attraction.
As their original attraction is weakened by heat and motion, their
expansion is increased by repulsion; and as they revolve, and recede
from each other in this way, they are fitted, by the change in their
modification, to involve each other, and from new attractions combining
with each other into new substances, according to affinity, under
changes induced in their nature conducive to this end, which not being
exactly known, cannot at present be fully defined. In every brewing, or
preparation of saccharine fluid for fermentation, the following
phenomena occur: first, _heat_ is either disengaged or fixed: secondly,
an _elastic fluid_ is either formed or absorbed in a nascent state:
these two indisputable facts form the uniform and invariable phenomena
of fermentation, and may be admitted as an established _axiom_, that
the proportions, extrication, and action of heat, with the fermentation
and fixation of elastic fluids, during the process, are the foundation
of the vinous products of the fermenting fluid. In conformity to so
rational a theory, I have for many years regulated my practice, the
result of which is the object of these papers. These, therefore, are
the three great objects which should engage our attention; not only
in fermentation, but in every similar process in chemistry, and are
the fundamental principles of our doctrine. FERMENTATION being not
only a decomposition of the fermentable matter, but of the water of
the fluid also; and the fixed air formed during the process being
composed of the hydrogen and oxygen of the fermentable matter, and
the water of the fluid also, there is a perpetual decomposition and
recomposition of that water, which gives fluidity to the whole mass,
taking place during the continuance of the process, part of the
hydrogen and oxygen of which escapes under the form of fixed air, for
want of a proper substance being presented of affinity enough to
absorb and combine with it into wine, beer, or spirit, or some other
necessary assistance in heat, light, motion, oxygen, hydrogen, carbon,
&c. or an intermedium to facilitate the formation of wine, beer, or
spirit, in preference to fixed air. Fixed air, or carbonic acid gas,
consists of about twenty-five parts of oxygen, and nine of carbon,
devested of the mucilage and yest that rises with it. It should be
recollected, that the decomposition of pyrites, the formation of
nitre, respiration, fermentation, &c. are low degrees of combustion,
and though it is the property of combustion to form fixed and
phlogisticated airs, both the modes of doing it, and the quantity of
the products, depend on the manner of oxygenating them in the changes
brought about by the different modes of combustion, or fermentation in
the vinous, acetous, and putrid process, which show the affinity
between them.
Fermentation is a subsequent _low combustion_ of the vegetable oxydes
or grain, that has undergone a previous, but partial combustion,
something like the slightly charring, or oxydating of wood or
pit-coal, by which the oxygenation is incomplete in both, and rendered
more complete in the former. An ultimate combustion of the fermentable
matter employed, is found only in the putrid process of fermentation,
which is a final or total decomposition of vegetable and animal
substances, in the actual combustion or burning of wood, charcoal, or
bones.
In the vinous process we have seen the escape of carbonic acid gas; in
the acetous process there is a great escape of azotic gas, or
phlogisticated air, from the decomposition of the air of the atmosphere
consumed in this process, which consists of about two-thirds of azotic
gas, and one third of oxygen gas,[3] the oxygenous part being absorbed
in the acetous process, and azotic set free with more or less hydrogen
and acetic gas, proportioned to the existing heat. If the heat is
beyond a certain degree, a portion of the ethereal part of the
new-formed acid escapes also.
[3] Twenty-seven parts of oxygen gas, and seventy-three of azotic
gas.
In the putrid process, the hydrogen escapes under the acriform shape of
inflammable air and azotic gas, and nothing more remains than mere
earth or water, or both, as the case may be, which is exactly similar
to other combustions, of which nothing remains, (if we except
phosphorus) but earth or ashes, with what small portion of alkaline or
other salts they may contain. This alkaline matter being present during
the formation of carbonic and azotic gas, absorbs, to saturation, a due
proportion of them, and generates _tartar_.
Experience has taught us the truth or justness of this definition, and
though it has brought us acquainted with the results of those three
stages of fermentation, combustion, or decomposition, we have certainly
overlooked the means of applying them with all the advantage they admit
of in the business which is the subject of these papers, and which a
little time and close observation must convince us of; and how much has
been hitherto lost, with the means of saving it in future, shall be
presently explained, and particularly pointed out.
In the prosecution of this design, where I may not be able to give an
unexceptionable demonstration, I hope always to be provided with a
practical proof, which may prove equally beneficial.
Let us now see what passes in a state of low combustion, such as may be
the result of fermentation in vegetables, arising from heat, moisture,
and motion, when impacted together. The most obvious occurrence of this
nature is found in new hay, which, under these circumstances, for want
of care and attention, often spontaneously takes fire, particularly in
wet seasons.
Fermentation, being one of the lowest degrees of combustion, is here
the spontaneous effect of the moist hay being impacted together, and
not properly made, that is, without the superfluous juices being dried
out of it, by which it retains a sufficient degree of fluidity or
moisture to begin a fermentation, in which heat and motion are
generated, and light, in a nascent state, extricated; these appearances
accumulated and accelerated by incumbent pressure, the redundant
moisture being soon exhausted, and the heat and motion increasing, the
actual combustion of the mass takes place, which is much facilitated by
a decomposition of the water of this moisture, and the air of the
atmosphere, unavoidably insinuated between the interstices formed by
the fibres of the hay, as they are impacted together into cocks, or
stacks, breaks out into actual flame, or _light visible_. These are no
novel appearances, but such as fall within the observation of every
one; and the candid maltster will acknowledge, that from the same
cause, though differently produced, similar effects may, and sometimes
do, happen in the malt house, in the preparation of that modern
article of luxury, by which we are enabled to make malt wine; and
these instances are sufficient to prove fermentation to be a low
degree of combustion, and to both simplify and explain the justness of
this doctrine. The malting of corn is the first stage of vegetation,
low combustion, and fermentation.
From observation and reasoning on what passes before our eyes, we
discover the low species of fermentation, in which the malting of corn
consists, to be a low degree of combustion, which, for want of due
attention, may break out into actual flame. We were always acquainted
with the _effect_: now reasoning on the subject brings us to a
knowledge of the cause.
To any one well acquainted with the nature of fermentation, it must be
manifest, that the malt distillers have paid more attention, and made
greater progress in the improvement of the process than any other class
of men interested in the success, though far from having arrived at
their _ne plus ultra_.
The introduction of raw or unmalted corn; the close compactness of
their working tun, or fermenting backs; the order and progressive
succession with which they conduct the process; and the pains they
necessarily take to arrive at a perfect attenuation, by a long
protracted fermentation, with the early conviction of a reward
proportioned to their diligence, and the success attending their best
endeavours, when not frustrated by intervening causes, must be stronger
inducements with them to delight in this instructive process of
nature's formation, than with the brewer, who has not these immediate
tests to encourage his labours, which the others daily derive from
distillation, and which so quickly and uniformly terminates their
hazards and success. The principal object in their view being a high
and deliberate attenuation, with a full vinosity, without any further
regard to the quality or flavour of their mash, as the combination of
these qualities alone produces the required strength, in the cleanest
manner.
The brewer's cares are many, and of longer duration: he is the vintager
of our northern climates: his porter or ale should be an agreeable malt
wine, suited to the palate of the district or neighbourhood he lives
in, or, ultimately, to the taste of his customers. The time he has
allotted himself for attenuation was first founded in error, derived
from ignorance of the subject, and slavishly continued by that
invincible tyrant, custom. Hurry marks the progress of his fermentation,
which can only be corrected by his speedy mode of _cleansing_, and the
consequent but necessary perishing of a part. He must begin with more
accuracy at the mash tun than the malt distiller, as it is there he
must not only regulate the strength, but, partially, the flavour and
transparency of his malt wine. His object does not end with the malt
distiller's, nor, like his, concentre in one focal point, the solution
of the whole of the farina of the plant or grain employed, regardless
of milkiness or transparency; he must carefully take the heats of his
liquor, so as to solve and combine the qualities he has in view; which,
if he misses in the first mash, is partly irremediable in the succeeding
ones. His cares do not end here; independent of the minutiæ of
fermentation and cleansing, he has the flavour, fining, and bringing
forward of his _malt wines_, nearly as much as the strength, to consider
and employ his attention.
It will scarcely be supposed that I would make these observations
merely with a view of drawing this comparison, though even it might
throw some light on the subject, without an attempt at supplying the
defects pointed out, and remedying the evils represented.
When the carbonic acid gas, or fixed air, so often mentioned in these
papers may be rendered subservient to part of the improvements I have
in view, and which is the constant, abundant, and uniform result of low
combustion, or vinous fermentation, in proportion of thirty-five pounds
weight to every hundred of saccharine or fermentable matter, fermented
in a due proportion of liquor, or water; from the decomposition of
which last, and the absorption of its oxygen, it is principally
obtained.
We have previously seen that one hundred pounds of fermentable matter
consists of eight pounds of hydrogen, twenty-eight of carbon, and
sixty-four pounds of oxygen; we have also seen that about thirty-five
pounds of carbon is extricated and detached from this quantity of
fermentable matter, properly diluted in water during fermentation;
allowing the usual quantity of spirit at the same time to be formed by
the process of this superfluous carbon, (as it now appears) must come
principally from that decomposition of the water of dilution, and not
from saccharine matter employed, which contains altogether but
twenty-eight pounds of carbon, the whole of which must necessarily go
to the formation of the fifty-seven pounds of dry alcohol produced.
But not to descend too deeply into particulars that might lead into
discussions not absolutely necessary in this place, let us take the
produce of ten gallons of ardent spirit, at one to ten over proof. We
here find that much more carbon has been generated, and given to the
atmosphere, than went to the composition of this quantity of spirit,
independent of the large quantity of alcohol dissolved in, and carried
off by it, in its flight as before observed.
Allowing the average quantity of fermentable matter in a quarter of
malt, barley, or other grain, to be only seventy-five pounds, then four
quarters will be equal to three hundred subtile pounds of raw sugar; or
eighty quarters of the one will be equal to six thousand pounds of the
other, or three tuns weight of unadulterated molasses.
If we estimate the superfluous carbonic acid gas of this quantity of
materials at only twenty-eight pounds per hundred, that will be sixteen
hundred and eighty pounds dissipated during the fermentation, which is
a loss, on every brewing of this quantity of materials, of upwards of
forty-one gallons of spirit, of the strength of one to ten.
What is computed here in spirit, may easily be applied to wine, porter,
beer, ale, sweets, &c. In barrels allowing three gallons and three
quarts of spirit per barrel to the former, and four gallons per barrel
to the latter, which gives eleven barrels and three quarters of the
one, and ten barrels and a quarter of the other, lost on each brewing
of eighty quarters of malt, or the average of that quantity of other
materials, by the mismanagement of the fermentation in one point only.
It must appear evident to every person capable of investigating this
calculation, that every six or seven pounds of carbon, fixed upon each
quarter of malt, or other materials, there will be an augmentation of
gravity or strength on this number of quarters, of ten or twelve
barrels each brewing; that is, every six or seven pounds of this
fugitive carbon that we arrest and fix in the fermenting fluid, as a
component part of the subsequent produce, by presenting the requisite
portion of oxygen and hydrogen, for the purpose within the sphere of
each others attraction, we increase our strength in the before-mentioned
_ratio_. It is of little moment whether this redundant gas comes from
the water of dilution or from the fermentable matter, as under, if we
can by any means turn it to account.
We have presumed the average quantity of fermentable matter at
seventy-five pounds per quarter; this must be evidently on the best
goods; this will give us a length of three barrels per quarter of malt
of eight bushels, of twenty-five pounds per barrel, specific gravity.
Suppose the apparent attenuation of these goods to be nineteen pounds,
the transparent gravity will be six pounds per barrel, viz.
Gravity of the worts in the cooler just before letting
down into the guile-tun, per barrel, 25 lb.
Apparent attenuation per barrel, 19 lb.
Transparent gravity per barrel, 6
--- 25 lb.
Or take it as it really is, viz. specific gravity
per barrel, 25 lb.
Real attenuation per barrel, 13 lb. 8 oz.
Yest and lees, 5 8
--------
19 lb.
Gravity per barrel, when transparent, 6
--- 25 lb.
It may be said that nineteen pounds is the real attenuation, and the
yest and lees produced is part thereof, as the fluid, or beer, in a
state of transparency is but six pounds per barrel specific gravity,
and it may, in some degree, be allowed to be so, as there is really so
much gravity lost during the process of fermentation. If we multiply
thirteen pounds eight ounces, which I have called the real attenuation,
by four, we shall find the result to be fifty-four pounds, which is
nineteen pounds more of superfluous gas upon four barrels of worts, of
twenty-five pounds gravity each, than is extricated from an equivalent
quantity of saccharine matter; that is, from one hundred pounds of raw
sugar or one hundred and twelve pounds of molasses, and their
respective waters of dilution, when the yest and lees do not exceed
five pounds eight ounces per barrel. This may be truly called an
analysis of the fermentable matter, giving the component parts
tolerably exact; though much depends on the management of the
fermentation, and the subsequent cleansing. By this analysis it
appears, that the mucilage of malt, or grain, gives out more gas than
the mucilage of sugar; and leaves a doubt on the mind whether to
adjudge the superfluous gas to the fermentable matter, or to the water
of dilution, or partly to both; but so it is, that these are the
products, whatever source we derive them from, and there is no denying
facts. The yest first added is not brought into this account.
There is a great similarity of appearance between the two species of
low combustion, fermentation and respiration. Fermentation, like
respiration, is the spontaneous effort of involuntary motion to
decomposition; and in the fermenting mass, as in the animal system, it
raises the temperature of both above that of the surrounding
atmosphere: that is, it is the cause of heat and involuntary motion,
both in the fermenting mass and in the animal system; and, like slow
combustion, consumes both, and resolves them into their first
principles, from which tendency the latter is constantly withheld by
the ingesta, fuel, or food, thrown in. I am well aware I must not carry
this reasoning any further.
Deep investigation may be thought not to be the object of our research;
but we must always have two things in view in inquiries of this nature;
indeed, in every pursuit of useful knowledge, where, like the present,
it is connected with the first principles, to pursue the winding path
of nature, through all her meanderings, up to the ultimate source of
these elements, which are the instruments of her operations; and when
we are favoured with a knowledge of these, either as the reward of
laboured assiduity and attention, or the result of chance, to copy the
original as close as we can.
I know I shall be justly accused with tautology. I must plead guilty to
the charge, not having leisure to apply the pruning hook of correction.
The misfortune is, that new doctrines must appear in a new dress, by
which they wear the garb of novelty, though, with respect to first
principles, there is nothing new under the sun; yet the application of
these principles might have remained in oblivion for ever if not called
into action. The man who in an age calls them into action, and
beneficially applies them for the good of that community of which he is
a member, may be virtually, though not literally, called the discoverer
of a principle. The man that projects, and the man that executes a
voyage of discovery, have superior claims to the man at the mast head
who first cries out land. The new turn that the discoveries of modern
philosophers has given to natural philosophy, requiring a change of
names as well as system; unusual words are unavoidably introduced to
express new terms of science, which gives a different character and
fashion to the whole, that I should have great pleasure in avoiding,
were it possible, which it obviously is not, finding it easier to glide
down the stream than oppose its torrent.