I. _Of the materials._

1. Barley, wheat, maize, and several other kinds of corn are capable of

undergoing those fermentative changes, by which beer may be made; but

the first substance is by far the fittest. There are two species of

barley, the _hordeum vulgare_ or common barley, having two seeds

arranged in a row on its spikes; and the _hordeum hexastichon_, in which

three seeds spring from one point, so that its double row has apparently

six seeds. The former is the proper barley, and is much the larger sized

grain; the latter is little known in England, but is much cultivated in

Scotland under the name of _bear_ or _big_; being a hardy plant adapted

to a colder country. The finer the climate in which barley grows the

denser and larger its seed, and the thinner its husk; thus the Norfolk

and Suffolk barley is distinguished in these respects from that of

Aberdeenshire. Big is a less compact grain than barley; the weight of a

Winchester bushel (2150·42 cubic inches) of the former is only about 47

libs, while that of a bushel of the latter is nearly 51 libs. Their

constituents, however, bear much the same proportion to each other.

The quality of barley is proved not only by its density when dry, but by

the increase of volume which it acquires when steeped in water. Thus,

100 measures of average English barley thereby swell into 124.

100 -- of -- Scotch ditto, 121.

100 -- of -- -- bigg or bear, 118.

Nay, 100 of very fine Suffolk barley have swollen into 183.

While 100 of an inferior Scotch bigg became no more than 109.

This circumstance indicates so nearly the probable yield of malt, that

it is carefully attended to by the officers of excise, who gauge the

steep cistern, and levy their duty in conformity with the largest

volume, 100 pounds of good barley become almost one half heavier by the

absorption of moisture; and weigh upon an average 147 pounds; the best

of course taking up most water.

By chemical analysis barley flour seems to consist of 67·18 parts of

hordeine, or starch and gluten intimately combined, 7·29 of vegetable

fibre, 1·15 of coagulated albumen, 3·52 parts of gluten, 5·21 of sugar,

4·62 of gum, 0·24 of phosphate of lime, and 9·37 of water. The loss

amounted to 1·42. To these principles should be added a peculiar

volatile oil of a concrete nature, which is obtained during the process

of distilling fermented malt wash. (See WHISKEY.) It may also be

extracted from barley flour, by the solvent action of alcohol; and never

amounts to more than a few parts in the thousand. The husk also contains

some of that fetid oil. Proust thought that he had discovered in barley

a peculiar principle, to which he gave the name of _hordeine_, and which

he separated from starch by the action of both cold and boiling water.

He found that by treating barley meal successively with water, he

obtained from 89 to 90 parts of a farinaceous substance, composed of

from 32 to 33 of starch, and from 57 to 58 of _hordeine_. Einhof

obtained from barley seeds, 70·05 of flour, 18·75 of husks or bran, and

11·20 of water.

According to Proust hordeine is a yellowish powder, not unlike fine

saw-dust. It contains no azote, for it affords no ammonia by

distillation, and is therefore very dissimilar to gluten. In the

germination of barley, which constitutes the process of malting, the

proportion of hordeine is greatly diminished by its conversion into

sugar and starch. Other chemists suppose that the _hordeine_ of Proust

is merely a mixture of the bran of the barley with starch and gluten. It

is obvious that the subject stands in need of new chemical researches.

In barley the husk constitutes from one fourth to one fifth of the whole

weight; in oats it constitutes one third; and in wheat, one tenth. From

the analysis of barley flour recently made, it appears to consist in

1000 parts: of water, 100; albumine, 22·3; sugar, 56; gum or mucilage,

50; gluten, 37·6; starch, 720; phosphate of lime, 2·5.

2. The hop, _humulus lupulus_, the female flowers of the plant. Ives

first directed attention to a yellow pulverulent substance which invests

the scales of the catkins, amounting to about one eighth of their

weight; and referred to it the valuable properties which hops impart to

beer. We may obtain this substance by drying the hops at a temperature

of 86° F., introducing them into a coarse canvass bag, and shaking it so

that the yellow powder shall pass through the pores of the canvass. This

powder bears some resemblance to lycopodium. Of the 13 parts in 100 of

this powder, 4 parts are foreign matters, derived from the scales of the

cones; leaving 9 parts of a peculiar granular substance. When distilled

with water, this substance affords two per cent. of its weight (2/10 for

100 times the weight of hops) of a volatile colourless oil, to which the

plant owes its peculiar aroma. This oil dissolves in water in

considerable quantity. It appears to contain sulphur (for it blackens

solutions of silver), and also acetate of ammonia. No less than 65 per

cent. of the yellow dust is soluble in alcohol. This solution, treated

with water and distilled, leaves a resin, which amounts to 52·5 per

cent. It has no bitter taste, and is soluble in alcohol and ether. The

watery solution from which the resin was separated contains the bitter

substance which has been called _lupuline_ by Payen and Chevallier,

mixed with a little tannin and malic acid. To obtain this in a state of

purity, the free acid must be saturated with lime, the solution

evaporated to dryness, and the residuum must be treated with ether,

which removes a little resin; after which the _lupuline_ is dissolved

out by alcohol, which leaves the malate of lime. On evaporating away the

alcohol, the lupuline remains, weighing from 8·3 to 12·5 per cent. It is

sometimes white, or slightly yellowish, and opaque, sometimes orange

yellow, and transparent. At ordinary temperatures it is inodorous, but

when heated strongly it emits the smell of hops. It possesses the

characteristic taste and bitterness of the hop. Water dissolves it only

in the proportion of 5 per cent., but it thereby acquires a pale yellow

colour. Lupuline is neither acid nor alkaline; it is acted upon neither

by the dilute acids nor alkalies, nor by the solutions of the metallic

salts: it is quite soluble in alcohol, but hardly in ether. It contains

apparently no azote, for it affords no ammonia by destructive

distillation; but only an empyreumatic oil.

The yellow dust of hops contains, moreover, traces of a fatty matter,

gum, a small quantity of an azotised substance, and several saline

combinations in minute quantity. Boiling water dissolves from 19 to 31

per cent., of the contents of the dust, of which a large proportion is

resin. Ives thought that the scales of the catkins of hops, when freed

from the yellow powder, contained no principles analogous to it; but

Payen and Chevallier have proved the contrary. The cones of hop give up

to boiling alcohol 36 per cent. of soluble matter; while the same cones,

stripped of their yellow powder, yield only 26 per cent.; and further,

these chemists found the same principles in the different parts of the

hop, but in different proportions.

The packing of the hop catkins or cones is one of the most important

operations towards the preservation of this plant; and is probably the

cause of the enormous difference in value between the English and French

hops after a few years’ keeping. The former, at the end of six years,

possess still great value, and may be sold as an article only two or

three years old; while the latter have lost the greater part of their

value in three years, and are no more saleable at the end of four. In

France, it is packed merely by tramping it with the feet in sacks. Under

this slight pressure, large interstitial spaces are left amid the mass

of the hops, through which the air freely circulates, carrying off the

essential oil, and oxygenating some of the other proximate principles,

so as to render them inert. By the English method, on the contrary, the

hops, after being well rammed into strong sacks hung in frames, are next

subjected to the action of a hydraulic press. The valuable yellow powder

thus inclosed on every side by innumerable compact scales, is completely

screened from the contact of the atmosphere, and from all its

vicissitudes of humidity. Its essential oil, in particular the basis of

its flavour, is preserved without decay.

According to the experiments of Chevallier and Payen upon the hops of

England, Flanders, the Netherlands, and the department of the Vosges,

those of the county of Kent afforded the largest cones, and were most

productive in useful secreted and soluble matters. Next to them were the

hops of Alost.

The best hops have a golden yellow colour, large cones, an agreeable

aroma; when rubbed between the hands, they leave yellow traces,

powerfully odoriferous, without any broken portions of the plant, such

as leaves, stems, and scaly fragments. When alcohol is digested on good

hops, from 9 to 12 per cent. of soluble yellow matter may be obtained by

evaporating it to dryness. This is a good test of their quality.

The best-flavoured and palest hops are packed in sacks of fine canvass,

which are called pockets, and weigh about 1-1/2 cwt. each. These are

bought by the ale brewer. The stronger-flavoured and darker-coloured

hops are packed in bags of a very coarse texture like door-mats, called

hop bags: these contain generally about 3 cwt., and are sold to the

porter and beer brewers. After the end of a year or two, hops are

reckoned to have lost much of their marketable value, and are then sold

to the second-rate porter brewers, under the name of old hops. The

finest hops are grown in the neighbourhood of Canterbury; but those of

Worcester have an agreeable mildness of flavour, greatly admired by many

ale drinkers. When the bitter and aromatic principles disappear, the

hops are no better than so much chaff; therefore, an accurate chemical

criterion of their principles would be a great benefit to the brewer.

II. _Malting._--This process consists of three successive operations;

the steeping; the couching, sweating, and flooring; and the kiln-drying.

The _steeping_ is performed in large cisterns made of wood or stone,

which being filled with clear water up to a certain height, a quantity

of barley is shot into them, and well stirred about with rakes. The good

grain is heavy, and subsides; the lighter grains, which float on the

surface, are damaged, and should be skimmed off; for they would injure

the quality of the malt, and the flavour of the beer made with it. They

seldom amount to more than two per cent. More barley is successively

emptied into the steep cistern, till the water stands only a few inches,

about five, above its surface; when this is levelled very carefully, and

every light seed is removed. The steep lasts from forty to sixty hours,

according to circumstances; new barley requiring a longer period than

old, and bigg requiring much less time than barley.

During this steep, some carbonic acid is evolved from the grains, and

combines with the water, which, at the same time, acquires a yellowish

tinge, and a strawy smell, from dissolving some of the extractive matter

of the barley husks. The grain imbibes about one half its weight of

water, and increases in size by about one-fifth. By losing this extract,

the husk becomes about one seventieth lighter in weight, and paler in

colour.

The duration of the steep depends, in some measure, upon the temperature

of the air, and is shorter in summer than in winter. In general from 40

to 48 hours will be found sufficient for sound dry grain. Steeping has

for its object to expand the farina of the barley with humidity, and

thus prepare the seed for germination, in the same way as the moisture

of the earth prepares for the growth of the radicle and plumula in seed

sown in it. Too long continuance in the steep is injurious; because it

prevents the germination at the proper time, and thereby exhausts a

portion of the vegetative power: it causes also an abstraction of

saccharine matter by the water. The maceration is known to be complete

when the grain may be easily transfixed with a needle, and is swollen to

its full size. The following is reckoned a good test:--If a barley-corn,

when pressed between the thumb and fingers, continues entire in its

husk, it is not sufficiently steeped; but if it sheds its flour upon the

fingers, it is ready. When the substance exudes in the form of a milky

juice, the steep has been too long continued, and the barley is spoiled

for germination.

In warm weather it sometimes happens that the water becomes acescent

before the grain is thoroughly swelled. This accident, which is manifest

to the taste and smell, must be immediately obviated by drawing off the

foul water through the tap at the bottom of the cistern, and replacing

it with fresh cold water. It does no harm to renew it two or three times

at one steep.

The _couch_.--The water being drawn off, and occasionally a fresh

quantity passed through, to wash away any slimy matter which may have

been generated in warm weather, the barley is now laid upon the couch

floor of stone flags, in square heaps from 12 to 16 inches high, and

left in that position for 24 hours. At this period, the bulk of the

grain being the greatest, it may be gauged by the revenue officers if

they think fit. The moisture now leaves the surface of the barley so

completely, that it imparts no dampness to the hand. By degrees,

however, it becomes warm; the temperature rising 10° above the

atmosphere, while an agreeable fruity smell is evolved. At this time, if

the hand be thrust into the heap, it not only feels warm, but it gets

bedewed with moisture. At this sweating stage, the germination begins;

the fibrils of the radicle first sprout forth from the tip of every

grain, and a white elevation appears, that soon separates into three or

more radicles, which grow rapidly larger. About a day after this

appearance, the plumula peeps forth at the same point, proceeding thence

beneath the husk to the other end of the seed, in the form of a green

leaflet.

The greatest heat of the couch is usually about 96 hours after the

barley has been taken out of the steep. In consequence, the radicles

tend to increase in length with very great rapidity, and must be checked

by artificial means, which constitute the chief art of the maltster. He

now begins to spread the barley thinner on the floor, and turns it over

several times in the course of a day, bringing the portions of the

interior into the exterior surface. The depth, which was originally 15

or 16 inches, is lowered a little at every turning over, till it be

brought eventually down to three or four inches. Two turnings a day are

generally required. At this period of spreading or flooring, the

temperature in England is about 62°, and in Scotland 5 or 6 degrees

lower.

About a day after the radicles appear, the rudiments of the stem, or of

the plumula, sprout forth, called by the English maltsters the

_acrospire_. It issues from the same end of the seed as the radicle, but

turns round, and proceeds within the husk towards the other end, and

would there come forth as a green leaf, were its progress not arrested.

The malting, however, is complete before the acrospire becomes a leaf.

The barley couch absorbs oxygen and emits carbonic acid, just as animals

do in breathing, but to a very limited extent; for the grain loses only

three per cent. of its weight upon the malt floor, and a part of this

loss is due to waste particles. As the acrospire creeps along the

surface of the seed, the farina within undergoes a remarkable

alteration. The gluten and mucilage disappear, in a great measure, the

colour becomes whiter, and the substance becomes so friable that it

crumbles into meal between the fingers. This is the great purpose of

malting, and it is known to be accomplished when the plumula or

acrospire has approached the end of the seed. Now the further growth

must be completely stopped. Fourteen days may be reckoned the usual

duration of the germinating stage of the malting operations in England;

but in Scotland, where the temperature of the couch is lower, eighteen

days or even twenty-one, are sometimes required. The shorter the period

within the above limits, the more advantageous is the process to the

maltster, as he can turn over his capital the sooner, and his malt is

also somewhat the better. Bigg is more rapid in its germination than

barley, and requires to be still more carefully watched. In dry weather

it is sometimes necessary to water the barley upon the couch.

Occasionally the odour disengaged from the couch is offensive,

resembling that of rotten apples. This is a bad prognostic, indicating

either that the barley was of bad quality, or that the workmen, through

careless shovelling, have crushed a number of the grains in turning them

over. Hence when the weather causes too quick germination, it is better

to check it by spreading the heap out thinner than by turning it too

frequently over. On comparing different samples of barley, we shall find

that the best develope the germ or acrospire quicker than the radicles,

and thus occasion a greater production of the saccharine principle; this

conversion advances along with the acrospire, and keeps pace with it, so

that the portion of the seed to which it has not reached, is still in

its unaltered starchy state. It is never complete for any single

barleycorn till the acrospire has come to the end opposite to that from

which it sprung; hence one part of the corn may be sugary, while the

other is still insipid. If the grain were allowed to vegetate beyond

this term, the radicles being fully one third of an inch long, the

future stem would become visibly green in the exterior; it would shoot

forth rapidly, the interior of the grain would become milky, with a

complete exhaustion of all its useful constituents, and nothing but the

husk would remain.

In France, the brewers, who generally malt their barley themselves,

seldom leave it on the couch more than 8 or 10 days, which, even taking

into account the warmer climate of their country, is certainly too short

a period, and hence they make inferior wort to the English brewer, from

the same quantity of malt.

At the end of the germination, the radicles have become 1-1/2 longer

than the barley, and are contorted so that the corns hook into one

another, but the acrospire is just beginning to push through. A moderate

temperature of the air is best adapted to malting; therefore it cannot

be carried on well during the heat of summer or the colds of winter.

Malt-floors should be placed in substantial thick-walled buildings,

without access of the sun, so that a uniform temperature of 59° or 60°

may prevail inside. Some recommend them to be sunk a little under the

surface of the ground, if the situation be dry.

During germination a remarkable change has taken place in the substance

of the grain. The glutinous constituent has almost entirely disappeared,

and is supposed to have passed into the matter of the radicles, while a

portion of the starch is converted into sugar and mucilage. The change

is similar to what starch undergoes when dissolved in water, and

digested in a heat of about 160°F. along with a little gluten. The

thick paste becomes gradually liquid, transparent, and sweet tasted, and

the solution contains now, sugar and gum, mixed with some unaltered

starch. The gluten suffers a change at the same time, and becomes

acescent, so that only a certain quantity of starch can be thus

converted by a quantity of gluten. By the artificial growth upon the

malt-floor, all the gluten and albumen present in barley are not

decomposed, and only about one half of the starch is converted into

sugar; the other half, by a continuance of the germination, would only

go to the growth of the roots and stems of the plant; but it receives

its nearly complete conversion into sugar without any notable waste of

substance in the brewer’s operation of mashing.

The _kiln-drying_.--When the malt has become perceptibly dry to the hand

upon the floor, it is taken to the kiln, and dried hard with artificial

heat, to stop all further growth, and enable it to be kept, without

change, for future use, at any time. The malt-kiln, which is

particularly described in the next page, is a round or a square chamber,

covered with perforated plates of cast iron, whose area is heated by a

stove or furnace, so that not merely the plates on which the malt is

laid are warmed, but the air which passes up through the stratum of malt

itself, with the effect of carrying off very rapidly the moisture from

the grains. The layer of malt should be about 3 or 4 inches thick, and

evenly spread, and its heat should be steadily kept at from the 90th to

the 100th degree of Fahrenheit’s scale, till the moisture be mostly

exhaled from it. During this time the malt must be turned over at first

frequently, and latterly every three or four hours. When it is nearly

dry, its temperature should be raised to from 145° to 165°F., and it

must be kept at this heat till it has assumed the desired shade of

colour, which is commonly a brownish-yellow or a yellowish-brown. The

fire is now allowed to die out, and the malt is left on the plates till

it has become completely cool; a result promoted by the stream of cool

air, which now rises up through the bars of the grate; or the thoroughly

dry browned malt may, by damping the fire, be taken hot from the plates,

and cooled upon the floor of an adjoining apartment. The prepared malt

must be kept in a dry loft, where it can be occasionally turned over

till it is used. The period of kiln-drying should not be hurried. Many

persons employ two days in this operation.

According to the colour and the degree of drying, malt is distributed

into three sorts; pale, yellow, and brown. The first is produced when

the highest heat to which it has been subjected is from 90° to 100° F.;

the amber yellow, when it has suffered a heat of 122°; and the brown

when it has been treated as above described. The black malt used by the

porter brewer to colour his beer, has suffered a much higher heat, and

is partially charred. The temperature of the kiln should, in all cases,

be most gradually raised, and most equably maintained. If the heat be

too great at the beginning, the husk gets hard dried, and hinders the

evaporation of the water from the interior substance; and should the

interior be dried by a stronger heat, the husk will probably split, and

the farina become of a horny texture, very refractory in the mash-tun.

In general, it is preferable to brown malt, rather by a long-continued

moderate heat, than by a more violent heat of shorter duration, which is

apt to carbonise a portion of the mucilaginous sugar, and to damage the

article. In this way, the sweet is sometimes converted into a bitter

principle.

During the kiln-drying, the roots and acrospire of the barley become

brittle, and fall off; and are separated by a wire sieve whose meshes

are too small to allow the malt itself to pass through.

A quantity of good barley, which weighs 100 pounds, being judiciously

malted, will weigh, after drying and sifting, 80 pounds. Since the raw

grain, dried by itself at the same temperature as the malt, would lose

12 per cent. of its weight in water, the malt process dissipates out of

these remaining 88 pounds, only 8 pounds, or 8 per cent. of the raw

barley. This loss consists of--

1-1/2 per cent. dissolved out in the steep water,

3 -- dissipated in the kiln,

3 -- by the falling of the fibrils,

1/2 -- of waste.

The bulk of good malt exceeds that of the barley from which it was made,

by about 8 or 9 per cent.

The operation of kiln-drying is not confined to the mere expulsion of

the moisture from the germinated seeds; but it serves to convert into

sugar a portion of the starch which remained unchanged, and that in a

twofold way; first, by the action of the gluten upon the fecula at an

elevated temperature, as also by the species of roasting which the

starch undergoes, and which renders it of a gummy nature. (See STARCH.)

We shall have a proof of this explanation, if we dry one portion of the

malt in a naturally dry atmosphere, and another in a moderately warm

kiln; the former will yield less saccharine extract than the latter.

Moreover, the kiln-dried malt has a peculiar, agreeable, and faintly

burned taste, probably from a small portion of empyreumatic oil formed

in the husk, and which not only imparts its flavour to the beer, but

also contributes to its preservation. It is therefore obvious, that the

skilful preparation of the malt must have the greatest influence both on

the quantity and quality of the worts to be made from it. If the

germination be pushed too far, a part of the extractible matter is

wasted; if it has not advanced far enough, the malt will be too raw, and

too much of its substance will remain as an insoluble starch; if it is

too highly kiln-dried, a portion of its sugar will be caramelised, and

become bitter; and if the sweating was imperfect or irregular, much of

the barley may be rendered lumpy and useless. Good malt is

distinguishable by the following characters:--

The grain is round and full, breaks freely between the teeth, and has a

sweetish taste, an agreeable smell, and is full of a soft flour from end

to end. It affords no unpleasant flavour on being chewed; it is not

hard, so that when drawn along an oaken table across the fibres, it

leaves a white streak, like chalk. It swims upon water, while unmalted

barley sinks in it. Since the quality of the malt depends much on that

of the barley, the same sort only should be used for one malting. New

barley germinates quicker than old, which is more dried up; a couch of a

mixture of the two would be irregular, and difficult to regulate.

[Illustration: 97 98 99 100]

_Description of the malt kiln._--_Figs._ 97, 98, 99, 100. exhibit the

construction of a well-contrived _malt kiln_. _Fig._ 97. is the ground

plan; _fig._ 98. is the vertical section; and _figs._ 99. and 100., a

horizontal and vertical section in the line of the malt-plates. The same

letters denote the same parts in each of the figures. A cast-iron

cupola-shaped oven is supported in the middle, upon a wall of brickwork

four feet high; and beneath it, are the grate and its ash-pit. The smoke

passes off through two equi-distant pipes into the chimney. The oven is

surrounded with four pillars, on whose top a stone lintel is laid: _a_

is the grate, 9 inches below the sole of the oven _b_; _c c c c_ are the

four nine-inch strong pillars of brickwork which bear the lintel _m_; _d

d d d d d_ are strong nine-inch pillars, which support the girder and

joists upon which perforated plates repose; _e_ denotes a vaulted arch

on each of the four sides of the oven; _f_ is the space between the kiln

and the side arch, into which a workman may enter, to inspect and clean

the kiln; _g g_, the walls on either side of the kiln, upon which the

arches rest, _h_, the space for the ashes to fall; _k_, the fire-door of

the kiln; _l l_, junction-pieces to connect the pipes _r r_ with the

kiln; the mode of attaching them is shown in _fig._ 99. These

smoke-pipes lie about three feet under the iron plates, and at the same

distance from the side walls; they are supported upon iron props, which

are made fast to the arches. In _fig._ 98., _u_ shows their section; at

_s s_, _fig._ 99., they enter the chimney, which is provided with two

register or damper plates, to regulate the draught through the pipes.

These registers are represented by _t t_, _fig._ 100., which shows a

perpendicular section of the chimney. _m_, _fig._ 98., is the lintel

which causes the heated air to spread laterally instead of ascending in

one mass in the middle, and prevents any combustible particles from

falling upon the iron cupola. _n n_ are the main girders of iron for the

iron beams _o o_, upon which the perforated plates _p_ lie; _q_, _fig._

98., is the vapour pipe in the middle of the roof, which allows the

steam of the drying malt to escape. The kiln may be heated either with

coal or wood.

The size of this kiln is about 20 feet square; but it may be made

proportionally either smaller or greater. The perforated floor should be

large enough to receive the contents of one steep or couch.

The perforated plate might be conveniently heated by steam pipes, laid

zig-zag, or in parallel lines under it; or a wire-gauze web might be

stretched upon such pipes. The wooden joists of a common floor would

answer perfectly to support this steam-range, and the heat of the pipes

would cause an abundant circulation of air. For drying the pale malt of

the ale brewer, this plan is particularly well adapted.

The kiln-dried malt is sometimes ground between stones in a common corn

mill, like oatmeal; but it is more generally crushed between iron

rollers, at least for the purposes of the London brewers.

[Illustration: 101 102]

The _crushing mill_.--The cylinder malt-mill is constructed as shown in

_fig._ 101, 102. I is the sloping-trough, by which the malt is let down

from its bin or floor to the hopper A of the mill, whence it is

progressively shaken in between the rollers B D. The rollers are of

iron, truly cylindrical, and their ends rest in bearers of hard brass,

fitted into the side frames of iron. A screw E goes through the upright,

and serves to force the bearer of the one roller towards that of the

other, so as to bring them closer together when the crushing effect is

to be increased. G is the square end of the axis, by which one of the

rollers may be turned either by the hand or by power; the other derives

its rotatory motion from a pair of equal-toothed wheels H, which are

fitted to the other end of the axes of the rollers. _d_ is a catch which

works into the teeth of a ratchet-wheel on the end of one of the rollers

(not shown in this view). The lever _c_ strikes the trough _b_ at the

bottom of the hopper, and gives it the shaking motion for discharging

the malt between the rollers, from the slide sluice _a_. _e e_, _fig._

101., are scraper-plates of sheet iron, the edges of which press by a

weight against the surfaces of the rollers, and keep them clean.

Instead of the cylinders, some employ a crushing mill of a

conical-grooved form like a coffee mill, upon a large scale. (_See the

general plan, infrà._)

The _mashing and boiling_.--Mashing is the operation by which the wort

is extracted, or eliminated from the malt, and whereby a

saccharo-mucilaginous extract is made from it. The malt should not in

general be ground into a fine meal, for in that case it would be apt to

form a cohesive paste with hot water, or to set, as it is called, and to

be difficult to drain. In crushed malt, the husk remains nearly entire,

and thus helps to keep the farinaceous particles open and porous to the

action of the water. The bulk of the crushed malt is about one-fifth

greater than that of the whole, or one bushel of malt gives a bushel and

a quarter of crushed malt. This is frequently allowed to lie a few days

in a cool place, in order that it may attract moisture from the air,

which it does very readily by its hygrometric power. Thus, the

farinaceous substance which had been indurated in the kiln, becomes

soft, spongy, and fit for the ensuing process of watery extraction.

Mashing has not for its object merely to dissolve the sugar and gum

already present in the malt, but also to convert into a sweet mucilage

the starch which had remained unchanged during the germination. We have

already stated that starch, mixed with gluten, and digested for some

time with hot water, becomes a species of sugar. This conversion takes

place in the mash-tun. The malted barley contains not only a portion of

gluten, but _diastase_ more than sufficient to convert the starch

contained in it, by this means, into sugar.

The researches of Payen and Persoz show, that the mucilage formed by the

reaction of malt upon starch, may either be converted into sugar, or be

made into permanent gum, according to the temperature of the water in

which the materials are digested. We take of pale barley malt, ground

fine, from 6 to 10 parts, and 100 parts of starch; we heat, by means of

a water-bath, 400 parts of water in a copper, to about 80°F.; we then

stir in the malt, and increase the heat to 140°F., when we add the

starch, and stir well together. We next raise the temperature to 158°,

and endeavour to maintain it constantly at that point, or at least to

keep it within the limits of 167° on the one side, and 158° on the

other. At the end of 20 or 30 minutes, the original milky and pasty

solution becomes thinner, and soon after as fluid nearly as water. This

is the moment in which the starch is converted into gum, or into that

substance which the French chemists call _dextrine_, from its power of

polarising light to the right hand, whereas common gum does it to the

left. If this merely mucilaginous solution, which seems to be a mixture

of gum with a little liquid starch and sugar, be suitably evaporated, it

may serve for various purposes in the arts to which gum is applied, but

with this view, it must be quickly raised to the boiling point, to

prevent the farther operation of the malt upon it. If we wish, on the

contrary, however, to promote the saccharine fermentation, for the

formation of beer, we must maintain the temperature at between 158° and

167° for three or four hours, when the greatest part of the gum will

have passed into sugar, and by evaporation of the liquid at the same

temperature, a starch syrup may be obtained like that procured by the

action of sulphuric acid upon starch. The substance, which operates in

the formation of sugar, or is the peculiar ferment of the sugar

fermentation, may be considered as a residuum of the gluten or vegetable

albumen in the germinating grain: it is reckoned by Payen and Persoz, a

new proximate principle called _diastase_, which is formed during

malting, in the grains of barley, oats, and wheat, and may be separated

in a pure state, if we moisten the malt flour for a few minutes in cold

water, press it out strongly, filter the solution, and heat the clear

liquid in a water bath, to the temperature of 158°. The greater part of

that albuminous azotised substance is thus coagulated, and is to be

separated by a fresh filtration; after which, the clear liquid is to be

treated with alcohol, when a flocky precipitate appears, which is

_diastase_. To purify it still further, especially from the azotised

matter, we should dissolve it in water, and precipitate again with

alcohol. When dried at a low temperature, it appears as a solid white

substance, which contains no azote; is insoluble in alcohol, but

dissolves in water and proof spirit. Its solution is neutral and

tasteless; when left to itself, it changes with greater or less rapidity

according to the temperature, and becomes sour at a temperature of from

149° to 167°. It has the property of converting starch into gum

(dextrine) and sugar, and indeed, when sufficiently pure, with such

energy that one part of it disposes 2000 parts of dry starch to that

change, but it operates the quicker the greater its quantity. Whenever

the solution of diastase with starch or with dextrine is heated to the

boiling point, it loses the sugar-fermenting property. One hundred parts

of well-malted starch appear to contain about one part of this

substance.

We can now understand the theory of malting, and the limits between

which the temperature of the liquor, ought to be maintained in this

operation; namely, the range between 157° and 160°F. It has been

ascertained as a principle in mashing, that the best and soundest

extract of the malt, is to be obtained, first of all, by beginning to

work with water at the lowest of these heats, and to conclude the mash

with water at the highest. Secondly, not to operate the extraction at

once with the whole of the water that is to be employed; but with

separate portions and by degrees. The first portion is added with the

view of penetrating equally the crushed malt, and of extracting the

already formed sugar; the next for effecting the sugar fermentation by

the action of the diastase. By this means also, the starch is not

allowed to run into a cohesive paste, and the extract is more easily

drained from the poorer mass, and comes off in the form of a nearly

limpid wort. The thicker moreover, or the less diluted the mash is, so

much the easier is the wort fined in the boiler or copper by the

coagulation of the albuminous matter: these principles illustrate, in

every condition, the true mode of conducting the mashing process; but

different kinds of malt require a different treatment. Pale and slightly

kilned malt requires a somewhat lower heat than malt highly kilned,

because the former has more undecomposed starch, and is more ready to

become pasty. The former also, for the same reason, needs a more

leisurely infusion than the latter, for its conversion into mucilaginous

sugar. The more sugar the malt contains, the more is its saccharine

fermentation accelerated by the action of the diastase. What has been

here said of pale malt, is still more applicable to the case of a

mixture of raw grain with malt, for it requires still gentler heats, and

more cautious treatment.

III. The mash-tun is a large circular tub with a double bottom; the

uppermost of which is called a false bottom, and is pierced with many

holes. There is a space of about 2 or 3 inches between the two, into

which the stopcocks enter, for letting in the water and drawing off the

wort. The holes of the false bottom should be burned, and not bored, to

prevent the chance of their filling up by the swelling of the wood,

which would obstruct the drainage: the holes should be conical, and

largest below, being about 3/8 of an inch there, and 1/8 at the upper

surface. The perforated bottom must be fitted truly at the sides of the

mash-tun, so that no grains may pass through. The mashed liquor is let

off into a large back, from which it is pumped into the wort coppers.

The mash-tun is provided with a peculiar rotatory apparatus for

agitating the crushed grains and water together, which we shall

presently describe. The size of the wort copper is proportional to the

amount of the brewing, and it must, in general, be at least so large as

to operate upon the whole quantity of wort made from one mashing; that

is, for every quarter of malt mashed, the copper should contain 140

gallons. The mash-tun ought to be at least a third larger, and of a

conical form, somewhat wider below than above. The quantity of water to

be employed for mashing, or the extraction of the wort, depends upon the

greater or less strength to be given to the beer. The seeds of the

crushed malt, after the wort is drawn off, retain still about 32 gallons

of water for every quarter of malt. In the boiling, and evaporation from

the coolers, 40 gallons of water are dissipated from one quarter of

malt; constituting 72 gallons in all. If 13 quarters of barley be taken

to make 1500 gallons of beer, 2400 gallons of water must therefore be

required for the mashing. This example will give an idea of the

proportions for an ordinary quality of beer.

When the mash is to begin, the copper must be filled with water, and

heated. As soon as the water has attained the heat of 145° in summer, or

167° in winter, 600 gallons of it are to be run off into the mash-tun,

and the 13 quarters of crushed malt are to be gradually thrown in and

well intermixed by proper agitation, so that it may be uniformly

moistened, and no lumps may remain. After continuing the agitation in

this way for one half or three-quarters of an hour, the water in the

copper will have approached to its boiling point, when 450 gallons at

the temperature of about 200° are to be run into the mash-tun, and the

agitation is to be renewed till the whole assumes an equally fluid

state: the tun is now to be well covered for the preservation of its

heat, and to be allowed to remain at rest for an hour, or an hour and a

half. The mean temperature of this mash may be reckoned at about 145°.

The time which is necessary for the transmuting heat of the remaining

starch into sugar depends on the quality of the malt. Brown malt

requires less time than pale malt, and still less than a mixture with

raw grain, as already explained. After the mash has rested the proper

time, the tap of the tun is opened, and the clear wort is to be drawn

out into the under back. If the wort that first flows is turbid, it must

be returned into the tun, till it runs clear. The amount of this first

wort may be about 675 gallons. Seven hundred and fifty gallons of water

at the temperature of 200° are now to be introduced up through the

drained malt, into the tun, and the mixture is to be agitated till it

becomes uniform, as before. The mash-tun is then to be covered, and

allowed to remain at rest for an hour. The temperature of this mash is

from 167° to 174°. While the second mash is making, the worts of the

first are to be pumped into the wort copper, and set a-boiling as

speedily as possible. The wort of the second mash is to be drawn off at

the proper time, and added to the copper as fast as it will receive it,

without causing the ebullition to stop.

A third quantity of water amounting to 600 gallons, at 200°, is to be

introduced into the mash-tun, and after half an hour, is to be drawn

off, and either pumped into the wort copper, or reserved for mashing

fresh malt, as the brewer may think fit.

The quantity of extract, per barrel weight, which a quarter of malt

yields to wort, amounts to about 84 lbs. The wort of the first extract

is the strongest; the second contains, commonly, one-half the extract of

the first; and the third, one-half of the second; according to

circumstances.

To measure the degrees of concentration of the worts drawn off from the

tun, a particular form of hydrometer, called a saccharometer, is

employed, which indicates the number of pounds weight of liquid

contained in a barrel of 36 gallons imperial measure. Now, as the barrel

of water weighs 360 lbs., the indication of the instrument when placed

in any wort, shows by how many pounds a barrel of that wort is heavier

than a barrel of water; thus, if the instrument sinks with its poise

till the mark 10 is upon a line with the surface of the liquid, it

indicates that a barrel of that wort weighs ten pounds more than a

barrel of water. See SACCHAROMETER.

Or, supposing the barrel of wort weighs 396 lbs., to convert that number

into specific gravity, we have the following simple rule:--

360 : 396 ∷ 100 : 1·100;

at which density, by my experiments, the wort contains 25 per cent., of

solid extract.

Having been employed to make experiments on the density of worts, and

the fermentative changes which they undergo, for the information of a

committee of the House of Commons, which sat in July and August, 1830, I

shall here introduce a short abstract of that part of my evidence which

bears upon the present subject.

My first object was to clear up the difficulties which, to common

apprehension, hung over the matter, from the difference in the scales

of the saccharometers in use among the brewers and distillers of England

and Scotland. I found that one quarter of good malt would yield to the

porter brewer a barrel Imperial measure of wort, at the concentrated

specific gravity of 1·234. Now, if the decimal part of this number be

multiplied by 360, being the number of pounds weight of water in the

barrel, the product will denote the excess in pounds, of the weight of a

barrel of such concentrated wort, over that of a barrel of water, and

that product is, in the present case, 84·24 pounds.

Mr. Martineau, jun., of the house of Messrs. Whitbread and Company, and

a gentleman connected with another great London brewery, had the

kindness to inform me that their average product from a quarter of malt

was a barrel of 84 lbs. gravity. It is obvious, therefore, that by

taking the mean operation of two such great establishments, I must have

arrived very nearly at the truth.

It ought to be remarked that such a high density of wort as 1·234 is not

the result of any direct experiment in the brewery, for infusion of malt

is never drawn off so strong; that density is deduced by computation

from the quantity and quality of several successive infusions; thus,

supposing a first infusion of the quarter of malt to yield a barrel of

specific gravity 1·112, a second to yield a barrel at 1·091, and a third

a barrel at 1·031, we shall have three barrels at the mean of these

three numbers, or one barrel at their sum, equal to 1·234.

I may here observe that the arithmetical mean or sum is not the true

mean or sum of the two specific gravities; but this difference is either

not known or disregarded by the brewers. At low densities this

difference is inconsiderable, but at high densities it would lead to

serious errors. At specific gravity 1·231, wort or syrup contains one

half of its weight of solid pure saccharum, and at 1·1045 it contains

one fourth of its weight; but the brewer’s rule, when here applied,

gives for the mean specific gravity 1·1155 = (1·231 + 1·000)/2.

The contents in solid saccharine matter at that density are however

27-1/4 per cent. showing the rule to be 2-1/4 lbs. wrong in excess on

100 lbs., or 9 lbs. per barrel.

The specific gravity of the solid dry extract of malt wort is 1·264; it

was taken in oil of turpentine, and the result reduced to distilled

water as unity. Its specific volume is 0·7911, that is, 10 lbs. of it

will occupy the volume of 7·911 lbs. of water. The mean specific

gravity, by computation of a solution of that extract in its own weight

of water, is 1·1166; but by experiment, the specific gravity of that

solution is 1·216, showing considerable condensation of volume in the

act of combination with water.

The following Table shows the relation between the specific gravities of

solutions of malt extract, and the per-centage of solid extract they

contain:

+-----+------+------------+-------+--------+

|Extr.|Water.|Malt Extract| Sugar |Specific|

|Malt.| | in 100. |in 100.|gravity.|

+-----+------+------------+-------+--------+

|600 +| 600 | 50·00 | 47·00 | 1·2180 |

|600 +| 900 | 40·0 | 37·00 | 1·1670 |

|600 +| 1200 | 33·3 | 31·50 | 1·1350 |

|600 +| 1500 | 28·57 | 26·75 | 1·1130 |

|600 +| 1800 | 25·00 | 24·00 | 1·1000 |

+-----+------+------------+-------+--------+

The extract of malt was evaporated to dryness, at a temperature of about

250° F., without the slightest injury to its quality, or any

empyreumatic smell. Bate’s tables have been constructed on solutions of

sugar, and not with solutions of extract of malt, or they agree

sufficiently well with the former, but differ materially from the

latter. Allan’s tables give the amount of a certain form of solid

saccharine matter extracted from malt, and dried at 175° F., in

correspondence to the specific gravity of the solution; but I have found

it impossible to make a solid extract from infusions of malt, except at

much higher temperatures than 175° F. Indeed, the numbers on Allan’s

saccharometer scale clearly show that his extract was by no means dry:

thus, at 1·100 of gravity he assigns 29·669 per cent. of solid

saccharine matter; whereas there is at that density of solid extract

only 25 per cent. Again, at 1·135, Allan gives 40 parts per cent. of

solid extract, whereas there are only 33-1/3 present.

By the triple mashing operations above described, the malt is so much

exhausted that it can yield no further extract useful for strong beer or

porter. A weaker wort might no doubt still be drawn off for small beer,

or for contributing a little to the strength of the next mashing of

fresh malt. But this I believe is seldom practised by respectable

brewers, as it impoverishes the grains which they dispose of for feeding

cattle.

The wort should be transferred into the copper, and made to boil as soon

as possible, for if it remains long in the under-back it is apt to

become acescent. The steam moreover raised from it in the act of boiling

serves to screen it from the oxygenating or acidifying influence of the

atmosphere. Until it begins to boil, the air should be excluded by some

kind of a cover.

Sometimes the first wort is brewed by itself into strong ale, the second

by itself into an intermediate quality; and the third into small beer;

but this practice is not much followed in this country.

We shall now treat of the boiling in of the hops. The wort drawn from

the mash-tun, whenever it is pumped into the copper, must receive its

allowance of hops. Besides evaporating off a portion of the water, and

thereby concentrating the wort, boiling has a twofold object. In the

first place, it coagulates the albuminous matter, partly by the heat,

and partly by the principles in the hops, and thereby causes a general

clarification of the whole mass, with the effect of separating the muddy

matters in a flocculent form. Secondly, during the ebullition, the

residuary starch and hordeine of the malt are converted into a limpid

sweetish mucilage, the _dextrine_ above described; while some of the

glutinous stringy matter is rendered insoluble by the tannin principle

of the hops, which favours still further the clearing of the wort. By

both operations the keeping quality of the beer is improved. This boil

must be continued during several hours; a longer time for the stronger,

and a shorter for the weaker beers. There is usually one seventh or one

sixth part of the water dissipated in the boiling copper. This process

is known to have continued a sufficient time, if the separation of the

albuminous flocks is distinct, and if these are found, by means of a

proof gauge suddenly dipped to the bottom, to be collected there, while

the supernatant liquor has become limpid. Two or three hours’ boil is

deemed long enough in many well-conducted breweries; but in some of

those in Belgium, the boiling is continued from 10 to 15 hours, a period

certainly detrimental to the aroma derived from the hop.

Many prefer adding the hops when the wort has just come to the boiling

point. Their effect is to repress the further progress of fermentation,

and especially the passage into the acetous stage, which would otherwise

inevitably ensue in a few days. In this respect, no other vegetable

production hitherto discovered can be a substitute for the hop. The

odorant principle is not so readily volatilised as would at first be

imagined; for when hop is mixed with strong beer wort, and boiled for

many hours, it can still impart a very considerable degree of its

flavour to weaker beer. By mere infusion in hot beer or water, without

boiling, the hop loses very little of its soluble principles. The tannin

of the hop combines, as we have said, with the vegetable albumen of the

barley, and helps to clarify the liquor. Should there be a deficiency of

albumen and gluten, in consequence of the mashing having been done at

such a heat as to have coagulated them beforehand, the defect may be

remedied by the addition of a little gelatine to the wort copper, either

in the form of calf’s foot, or of a little isinglass. If the hops be

boiled in the wort for a longer period than 5 or 6 hours, they lose a

portion of their fine flavour; but if their natural flavour be rank, a

little extra boiling improves it. Many brewers throw the hops in upon

the surface of the boiling wort, and allow them to swim there for some

time, that the steam may penetrate them, and open their pores for a

complete solution of their principles when they are pushed down into the

liquor. It is proper to add the hops in considerable masses, because in

tearing them asunder, some of the lupuline powder is apt to be lost.

The quantity of hop to be added to the wort varies according to the

strength of the beer, the length of time it is to be kept, or the heat

of the climate where it is intended to be sent. For strong beer, 4-1/2

lbs. of hops are required to a quarter of malt, when it is to be highly

aromatic and remarkably clear. For the stronger kinds of ale and porter,

the rule, in England, is to take a pound of hops for every bushel of

malt, or 8 lbs. to a quarter. Common beer has seldom more than a quarter

of a pound of hops to the bushel of malt.

It has been attempted to form an extract of hops by boiling in covered

vessels, so as not to lose the oil, and to add this instead of the hop

itself to the beer. On the great scale this method has no practical

advantage, because the extraction of the hop is perfectly accomplished

during the necessary boiling of the wort, and because the hop operates

very beneficially, as we have explained, in clarifying the beer. Such an

extract, moreover, could be easily adulterated.

_Of the Coolers._--The contents of the copper are run into what is

called the hop-back, on the upper part of which is fixed a drainer, to

keep back the hops. The pump is placed in the hop-back, for the purpose

of raising the wort to the coolers, usually placed in an airy situation

upon the top of the brewery. Two coolers are indispensable when we make

two kinds of beer from the same brewing, and even in single brewings,

called _gyles_, if small beer is to be made. One of these coolers ought

to be placed above the level of the other. As it is of great consequence

to cool the worts down to the fermenting pitch as fast as possible,

various contrivances have been made for effecting this purpose. The

common cooler is a square wooden cistern, about 6 inches deep, and of

such an extent of surface that the whole of one boil may only occupy 2

inches, or thereabouts, of depth in it. For a quantity of wort equal to

about 1500 gallons its area should be at least 54 feet long and 20 feet

wide. The seams of the cooler must be made perfectly water-tight and

smooth, so that no liquor may lodge in them when they are emptied. The

utmost cleanliness is required, and an occasional sweetening with

lime-water.

The hot wort reaches the cooler at a temperature of from 200° to 208°,

according to the power of the pump. Here it should be cooled to the

proper temperature for the fermenting tun, which may vary from 54° to

64°, according to circumstances. The refrigeration is accomplished by

the evaporation of a portion of the liquor: it is more rapid in

proportion to the extent of the surface, to the low temperature, and the

dryness of the atmosphere surrounding the cooler. The renewal of a body

of cool dry air by the agency of a fan, may be employed with great

advantage. The cooler itself must be so placed that its surface shall be

freely exposed to the prevailing wind of the district, and be as free as

possible from the eddy of surrounding buildings. It is thought by many,

that the agitation of the wort during its cooling, is hurtful. Were the

roof made moveable, so that the wort could be readily exposed, in a

clear night, to the aspect of the sky, it would cool rapidly by

evaporation, on the principles explained by Dr. Wells, in his “Essay on

Dew.”

When the cooling is effected by evaporation alone, the temperature falls

very slowly, even in cold air, if it be loaded with moisture. But when

the air is dry, the evaporation is vigorous, and the moisture exhaled

does not remain incumbent on the liquor, as in damp weather, but is

diffused widely in space. Hence we can understand how wort cools so

rapidly in the spring and autumn, when the air is generally dry, and

even more quickly than in winter, when the air is cooler, but loaded

with moisture. In fact, the cooling process goes on better when the

atmosphere is from 50° to 55°, than when it falls to the freezing point,

because in this case, if the air be still, the vapours generated remain

on the surface of the liquor, and prevent further evaporation. In summer

the cooling can take place only during the night.

In consequence of the evaporation during this cooling process, the bulk

of the worts is considerably reduced; thus, if the temperature at the

beginning was 208°, and if it be at the end 64°, the quantity of water

necessary to be evaporated to produce this refrigeration would be nearly

1/8 of the whole, putting radiation and conduction of heat out of the

question. The effect of this will be a proportional concentration of the

beer.

The period of refrigeration in a well-constructed cooler, amounts to 6

or 7 hours in favourable weather, but to 12 or 15 in other

circumstances. The quality of the beer is much improved by shortening

this period; because, in consequence of the great surface which the wort

exposes to the air, it readily absorbs oxygen, and passes into the

acetous fermentation with the production of various mouldy spots; an

evil to which ill-hopped beer is particularly liable. Various schemes

have been contrived to cool wort, by transmitting it through the

convolutions of a pipe immersed in cold water. The best plan is to

expose the hot wort for some hours freely to the atmosphere and the

cooler, when the loss of heat is most rapid by evaporation and other

means, and when the temperature falls to 100°, or thereby, to transmit

the liquor through a zig-zag pipe, laid almost horizontally in a trough

of cold water. The various methods described under _Refrigerator_ are

more complex, but they may be practised in many situations with

considerable advantage.

Whilst the wort reposes in the cooler, it lets fall a slight sediment,

which consists partly of fine flocks of coagulated albumen combined with

tannin, and partly of starch, which had been dissolved at the high

temperature, and separates at the lower. The wort should be perfectly

limpid, for a muddy liquor never produces transparent beer. Such beer

contains, besides mucilaginous sugar and gum, usually some starch, which

even remains after the fermentation, and hinders its clarifying, and

gives it a tendency to sour. The wort contains more starch the hotter it

has been mashed, the less hops have been added, and the shorter time it

has been boiled. The presence of starch in the wort may be made manifest

by adding a little solution of iodine in alcohol to it, when it will

become immediately blue. We thus see that the tranquil cooling of wort

in a proper vessel has an advantage over cooling it rapidly by a

refrigeratory apparatus. When the wort is sufficiently cool, it is let

down into the fermenting tun. In this transfer, the cooling might be

carried several degrees lower, were the wort made to pass down through a

tube inclosed in another tube, along which a stream of cold water is

flowing in the opposite direction, as we have described in the sequel of

ACETIC ACID. These fermenting tuns are commonly called _gyle-tuns_, or

working tuns, and are either square or circular, the latter being

preferable on many accounts.

IV. _Of the Fermentation._--In the great London breweries, the size of

these fermenting tuns is such that they contain from 1200 to 1500

barrels. The quantity of wort introduced at a time must, however, be

considerably less than the capacity of the vessel, to allow room for the

head of yeast which rises during the process; if the vessel be

cylindrical, this head is proportional to the depth of the worts. In

certain kinds of fermentation, it may rise to a third of that depth. In

general, the fermentation proceeds more uniformly and constantly in

large masses, because they are little influenced by vicissitudes of

temperature; smaller vessels, on the other hand, are more easily

handled. The _general_ view of fermentation will be found under that

title; I shall here make a few remarks on what is peculiar to beer.

During the fermentation of wort, a portion of its saccharine matter is

converted into alcohol, and wort thus changed, is beer. It is necessary

that this conversion of the sugar be only partial, for beer which

contains no undecomposed sugar would soon turn sour, and even in the

casks its alcohol undergoes a slow fermentation into vinegar. The amount

of this excess of sugar is greater in proportion to the strength of the

wort, since a certain quantity of alcohol, already formed, prevents the

operation of the ferment on the remaining wort. Temperature has the

greatest influence upon the fermentation of wort. A temperature of from

55° to 60° of the liquor, when that of the atmosphere is 55°, is most

advantageous for the commencement. The warmth of the wort as it comes

into the gyle-tun must be modified by that of the air in the apartment.

In winter, when this apartment is cold, the wort should not be cooled

under 64° or 60°, as in that case the fermentation would be tedious or

interrupted, and the wort liable to spoil or become sour. In summer,

when the temperature of the place rises to above 75°, the wort should be

cooled, if possible, down to 55°, for which purpose it should be let in

by the system of double pipes, above mentioned. The higher the

temperature of the wort, the sooner will the fermentation begin and end,

and the less is it in our power to regulate its progress. The expert

brewer must steer a middle course between these two extremes, which

threaten to destroy his labours. In some breweries a convoluted pipe is

made to traverse or go round the sides of the gyle-tun, through which

warm water is allowed to flow in winter, and cold in summer, so as to

modify the temperature of the mass to the proper fermenting pitch. If

there be no contrivance of this kind, the apartment may be cooled in

summer, by suspending wet canvas opposite the windows in warm weather,

and kindling a small stove within it in cold.

When the wort is discharged into the gyle-tun, it must receive its dose

of yeast, which has been previously mixed with a quantity of the wort,

and left in a warm place till it has begun to ferment. This mixture,

called _lobb_, is then to be put into the tun, and stirred well through

the mass. The yeast should be taken from similar beer. Its quantity must

depend upon the temperature, strength, and quantity of the wort. In

general, one gallon of yeast is sufficient to set 100 gallons of wort in

complete fermentation. An excess of yeast is to be avoided, lest the

fermentation should be too violent, and be finished in less than the

proper period of 6 or 8 days. More yeast is required in winter than

summer; for, at a temperature of 50°, a double quantity may be used to

that at 68°.

Six or eight hours after adding the yeast, the tun being meanwhile

covered, the fermentation becomes active: a white milky-looking froth

appears, first on the middle, and spreads gradually over the whole

surface; but continues highest in the middle, forming a frothy

elevation, the height of which increases with the progress of the

fermentation, and whose colour gradually changes to a bright brown, the

result, apparently, of the oxidation of the extractive contained in this

yeasty top. This covering screens the wort from the contact of the

atmospherical air. During this time, there is a perpetual disengagement

of carbonic acid gas, which is proportional to the quantity of sugar

converted into alcohol. The warmth of the fermenting liquid increases at

the same time, and is at a maximum when the fermentation has come to its

highest point. This increase of temperature amounts to from 9° to 14° or

upwards, and is the greater the more rapid the fermentation. But in

general, the fermentation is not allowed to proceed so far in the

gyle-tun, for after it is advanced a little way, the beer is _cleansed_,

that is, drawn off into other vessels, which are large barrels set on

end, with large openings in their top, furnished with a sloping tray for

discharging an excess of yeast into the wooden trough, in which the

_stillions_ stand. These _stillions_ are placed in communication with a

store-tub, which keeps them always full, by hydrostatic pressure, so

that the head of yeast may spontaneously flow over, and keep the body of

liquor in the cask clean. This apparatus will be explained in describing

the brewery plant. See the _figures, infrà_.

It must be observed, that the quantity of yeast, and the heat of

fermentation, differ for every different quality of beer. For mild ale,

when the fermentation has reached 75°, its first flavour begins; at 80°

the flavour increases; at 85° it approaches the high flavour; at 90° it

is high; but it may be carried to 100° and upwards, for particular

purposes. A wort of 30 lbs. per barrel (sp. gr. 1·088), ought to

increase about 15°, so that in order to arrive at 80°, it should be set

at 65°. The quantity of yeast for such an ale should be from 2 to 3 lbs.

per barrel. The higher the heat, the less yeast is necessary. If the

heat of the fermentation should at any time fall, it must be raised by a

supply of fresh yeast, well stirred in; but this practice is not

advisable in general, because rousing the worts in the gyle-tun is apt

to communicate a rank flavour of yeast to the ale. It is the practice of

many experienced brewers to look every 2 hours into the gyle-tun,

chiefly with the view of observing the progress of the heat, which is

low at first, but afterwards often increases half a degree per hour, and

subsequently declines, as the fermentation approaches its conclusion,

till at length the heat becomes uniform, or sometimes decreases, before

the fermentation is finished, especially where the quantity operated

upon is small.

Some brewers recommend, when the fermentation is carried to its utmost

period, to add about 7 lbs. of wheat or bean flour to a gyle-tun of 25

or 30 barrels, at the time of _cleansing_, so as to quicken the

discharge of the yeast, by disengagement of more carbonic acid. The

flour should be whisked up in a pail, with some of the beer, till the

lumps are broken, and then poured in. By early cleansing, the yeast is

preserved longer in a state proper for a perfect fermentation than by a

contrary practice.

For old ale, which is to be long kept, the heat of the fermentation

should not exceed 75°, but a longer time is required to complete the

fermentation and ensure the future good flavour of the ale.

For porter, the general practice is, to use from 4 to 4-1/2 lbs. of hops

per barrel for keeping; though what is termed mild or mixing porter, has

not more than 3 or 3-1/2 lbs. The heat of fermentation must not exceed

70°, and begin about 60°. If the heat tend to increase much above that

pitch in the gyle-tun, the porter should be _cleansed_, by means of the

_stillions_. At this period of the fermentation, care should be taken

that the sweetness of the malt be removed, for which purpose more yeast

may be used than with any other beer of the same strength. The quantity

is from 3 to 4 lbs. per barrel, rousing the wort in the gyle-tun every 2

hours in the day-time.

When the plan of _cleansing_ casks is not employed, the yeast is removed

from the surface of the fermenting tun by a skimmer, and the clear beer

beneath is then drawn off into the ripening tuns, called _store-vats_,

in which it is mixed up with different brewings, to suit the taste of

the customers. This transfer must take place whenever the extrication of

carbonic acid has nearly ceased; lest the alcohol formed should dissolve

some of the floating yeast, acquire thereby a disagreeable taste, and

pass partially into the acetous state.

In this process, during the formation of vinous spirit at the expense of

the sugar, the albumen and gluten diffused through the beer, being acted

upon by the alcohol, become insoluble; one portion of them is buoyed to

the top with the carbonic acid gas, to form the frothy yeast; and

another portion falls to form the bottom barm. The former consists of

the same materials as the wort, with a large proportion of gluten, which

forms its active constituent; the latter is a peculiar deposit,

consisting of the same gluten mixed with the various dense impurities of

the wort, and may be also used as a ferment, but is cruder than the

floating yeast. The amount of yeast is proportional to the activity of

the fermentation, or extrication of carbonic acid gas, as also to the

heat of the mashing process, and the quantity of starch or flour

unaltered by germination. Pale malt affords usually, more yeast than

malt highly kilned. When the yeast becomes excessive, from too violent

fermentation, it should be skimmed off from time to time, which will

tend to cool the liquor and moderate the intestine changes.

After the beer is let down into the close store-tuns in the cellar, an

obscure fermentation goes on, for a considerable period in its body,

which increases its spirituous strength, and keeps up in it a constant

impregnation of carbonic acid gas, so as to render it lively and

agreeable to the taste, when it is casked off for sale. It would appear,

that beer is never stationary in quality, while it is contained in the

tuns; for the moment when it ceases to improve by the decomposition of

its residuary sugar, it begins to degenerate into vinegar. This result

may be produced either by the exhaustion of the saccharine, or by the

fermentative matter. The store cellar should therefore be under ground,

free from alternations of temperature, vibrations of carriages, and as

cool as possible. In the great London breweries, the fermentation is

rendered very complete in the cleansing butts; so that a slow and steady

ripening is ensured in the great store-tuns. The gyle-tuns are too

capacious to permit the fermentation to be finished, with either safety

or sufficient dispatch in them.

V. OF RIPENING DIFFERENT KINDS OF BEER.--The varieties of beer depend

either upon the difference of their materials, or from a different

management of the brewing processes.

With regard to the materials, beers differ in the proportion of their

malt, hops, and water; and in the different kinds of malt or other

grain. To the class of table or small beers, all those sorts may be

referred whose specific gravity does not exceed 1·025, which contain

about 5 per cent. of malt extract, or nearly 18 pounds per barrel. Beers

of middling strength may be reckoned those between the density of 1·025

and 1·040; which contain, at the average, 7 per cent., or 25 pounds per

barrel. The latter may be made with 400 quarters of malt to 1500 barrels

of beer. Stronger beers have a specific gravity of from 1·050 to 1·080,

and take from 45 to 75 quarters of malt to the same quantity of beer.

The strongest beer found in the market is some of the English and Scotch

ales, for which from 18 to 27 quarters of malt are taken for 1500

gallons of beer. Good porter requires from 16 to 18 quarters for that

quantity. Beers are sometimes made with the addition of other

farinaceous matter to the malt; but when the latter constitutes the main

portion of the grain, the malting of the other kinds of corn becomes

unnecessary, for the diastase of the barley-malt changes the starch into

sugar during the mashing operation. Even with entirely raw grain, beer

is made in some parts of the Continent, the brewers trusting the

conversion of the starch into sugar to the action of the gluten alone,

at a low mashing temperature, on the principle of Saussure’s and

Kirchoff’s researches.

The colour of the beer depends upon the colour of the malt, and the

duration of the boil in the copper. The pale ale is made, as we have

stated, from steam or sun-dried malt, and the young shoots of the hop;

the deep yellow ale from a mixture of pale yellow and brown malt; and

the dark brown beer from well-kilned and partly carbonised malt, mixed

with a good deal of the pale, to give body. The longer and more strongly

heated the malt has been in the kiln, the less weight of extract,

_cæteris paribus_, does it afford. In making the fine mild ales, high

temperatures ought to be avoided, and the yeast ought to be skimmed off,

or allowed to flow very readily from its top, by means of the cleansing

butt system, so that little ferment being left in it to decompose the

rest of the sugar, the sweetness may remain unimpaired. With regard to

porter, in certain breweries, each of the three kinds of malt employed

for it is separately mashed, after which the first and the half of the

second wort is boiled along with the whole of the hops, and thence

cooled and set to ferment in the gyle-tun. The third drawn wort, with

the remaining half of the second, is then boiled with the same hops,

saved by the drainer, and, after cooling, added to the former in the

gyle-tun, when the two must be well roused together.

It is obvious, from the preceding development of principles, that all

amylaceous and saccharine materials, such as potatoes, beans, turnips,

as well as cane and starch syrup, molasses, &c., may be used in brewing

beer. When, however, a superior quality of brown beer is desired, malted

barley is indispensable, and even with these substitutes a mixture of it

is most advantageous. The washed roots of the common carrot, of the red

and yellow beet, or of the potato, must be first boiled in water, and

then mashed into a pulp. This pulp must be mixed with water in the

copper, along with wheaten or oat meal, and the proper quantity of hops,

then boiled during 8 or 9 hours. This wort is to be cooled in the usual

way, and fermented, with the addition of yeast. A much better process is

that now practised, on a considerable scale, at Strasbourg, in making

the ale, for which that city is celebrated. The mashed potatoes are

mixed with from a twentieth to a tenth of their weight of finely ground

barley malt, and some water. The mixture is exposed, in a water-bath, to

a heat of 160° F. for four hours, whereby it passes into a saccharine

state, and may then be boiled with hops, cooled, and properly fermented

into good beer.

Maize, or Indian corn, has also been employed to make beer; but its

malting is somewhat difficult on account of the rapidity and vigour with

which its radicles and plumula sprout forth. The proper mode of causing

it to germinate is to cover it, a few inches deep, with common soil, in

a garden or field, and to leave it there till the bed is covered with

green shoots of the plant. The corn must be then lifted, washed, and

exposed to the kiln.

_The Difference of the Fermentation._--The greater or less rapidity with

which the worts are made to ferment has a remarkable influence upon the

quality of the beer, especially in reference to its fitness for keeping.

The wort is a mucilaginous solution in which the yeastly principles,

eliminated by the fermentation, will, if favoured by regular and slow

intestine movements, completely rise to the surface, or sink to the

bottom, so as to leave the body fine. But, when the action is too

violent, these barmy glutinous matters get comminuted and dispersed

through the liquor, and can never afterwards be thoroughly separated. A

portion of the same feculent matter becomes, moreover, permanently

dissolved, during this furious commotion, by the alcohol that is

generated. Thus the beer loses not merely its agreeable flavour and

limpidity, but is apt to spoil from the slightest causes. The slower,

more regularly progressive, and less interrupted, therefore, the

fermentation is, so much better will the product be.

Beer, in its perfect condition, is an excellent and healthful beverage,

combining, in some measure, the virtues of water, of wine, and of food,

as it quenches thirst, stimulates, cheers, and strengthens. The vinous

portion of it is the alcohol, proceeding from the fermentation of the

malt sugar. Its amount, in common strong ale or beer, is about 4 per

cent., or four measures of spirits, specific gravity 0·825 in 100

measures of the liquor. The best brown stout porter contains 6 per

cent., the strongest ale even 8 per cent.; but common beer only one. The

nutritive part of the beer is the undecomposed gum-sugar, and the

starch-gum, not changed into sugar. Its quantity is very variable,

according to the original starch of the wort, the length of the

fermentation, and the age of the beer.

The main feature of good beer is fine colour and transparency; the

production of which is an object of great interest to the brewer.

Attempts to clarify it in the cask seldom fail to do it harm. The only

thing that can be used with advantage for _fining_ foul or muddy beer,

is isinglass. For porter, as commonly brewed, it is frequently had

recourse to. A pound of good isinglass will make about 12 gallons of

_finings_. It is cut into slender shreds, and put into a tub with as

much vinegar or hard beer as will cover it, in order that it may swell

and dissolve. In proportion as the solution proceeds, more beer must be

poured upon it, but it need not be so acidulous as the first, because,

when once well softened by the vinegar, it readily dissolves. The

mixture should be frequently agitated with a bundle of rods, till it

acquires the uniform consistence of thin treacle, when it must be

equalised still more by passing through a tammy cloth, or a sieve. It

may now be made up with beer to the proper measure of dilution. The

quantity generally used is from a pint to a quart per barrel, more or

less, according to the foulness of the beer. But before putting it into

the butt, it should be diffused through a considerable volume of the

beer with a whisk, till a frothy head be raised upon it. It is in this

state to be poured into the cask, briskly stirred about; after which the

cask must be bunged down for at least 24 hours, when the liquor should

be limpid. Sometimes the beer will not be improved by this treatment;

but this should be ascertained beforehand, by drawing off some of the

beer into a cylindric jar or phial, and adding to it a little of the

finings. After shaking and setting down the glass, we shall observe

whether the feculencies begin to collect in flocky parcels, which slowly

subside; or whether the isinglass falls to the bottom without making any

impression upon the beer. This is always the case when the fermentation

is incomplete, or a secondary decomposition has begun. Mr. Jackson has

accounted for this clarifying effect of isinglass in the following way.

The isinglass, he thinks, is first of all rather diffused mechanically,

than chemically dissolved, in the sour beer or vinegar, so that when the

finings are put into the foul beer, the gelatinous fibres, being set

free in the liquor, attract and unite with the floating feculencies,

which before this union were of the same specific gravity with the beer,

and therefore could not subside alone; but having now acquired

additional weight by the coating of fish-glue, precipitate as a

flocculent magma. This is Mr. Jackson’s explanation; to which I would

add, that if there be the slightest disengagement of carbonic acid gas,

it will keep up an obscure locomotion in the particles, which will

prevent the said light impurities, either alone or when coated with

isinglass, from subsiding. The beer is then properly enough called

_stubborn_ by the coopers. But the true theory of the action of

isinglass is, that the tannin of the hops combines with the fluid

gelatine, and forms a flocculent mass, which envelopes the muddy

particles of the beer, and carries them to the bottom as it falls, and

forms a sediment. When after the finings are poured in, no proper

precipitate ensues, it may be made to appear by the addition of a little

decoction of hop.

Mr. Richardson, the author of the well-known brewer’s saccharometer,

gives the following as the densities of different kinds of beer:--

+-----------------------+------------------+-----------------+

| Beer. |Pounds per Barrel.|Specific Gravity.|

+-----------------------+------------------+-----------------+

|Burton ale, 1st sort | 40 to 43 | 1·111 to 1·120 |

| 2d ditto | 35 to 40 | 1·097 to 1·111 |

| 3d ditto | 28 to 33 | 1·077 to 1·092 |

|Common ale | 25 to 27 | 1·070 to 1·073 |

|Ditto ditto | 21 | 1·058 |

|Porter, common sort | 18 | 1·050 |

|Ditto, double | 20 | 1·055 |

|Ditto, brown stout | 23 | 1·064 |

|Ditto, best brown stout| 26 | 1·072 |

|Common small beer | 6 | 1·014 |

|Good table beer | 12 to 14 | 1·033 to 1·039 |

+-----------------------+------------------+-----------------+

_Of Returns or Malt Residuums._--When small beer is brewed after ale or

porter, only one mash is to be made; but where this is not done, there

may be two mashes, in order to economise malt to the utmost. We may let

on the water at 160° or 165°, in any convenient quantity, infuse for an

hour or thereby, then run it off, and pump into the copper, putting some

hops into it, and causing it to boil for an instant; when it may be

transferred to the cooler. A second mash or return may be made in the

same manner, but at a heat 5° lower; and then disposed of in the boiler

with some hops, which may remain in the copper during the night at a

scalding heat, and may be discharged into the cooler in the morning.

These two returns are to be let down into the under-back immediately

before the next brewing, and thence heated in the copper for the next

mashing of fresh malt, instead of hot water, commonly called _liquor_,

in the breweries. But allowance must be made, in the calculation of the

worts, for the quantity of fermentable matter in these two returns. The

nett aggregate saving is estimated from the gravity of the return taken

when cold in the cooler. A slight economy is also made in the extra

boiling of the used hops. The lapse of a day or two between the

consecutive brewings is no objection to the method of _returns_, because

they are too weak in saccharine matter to run any risk of fermentation.

In conclusion, it may be remarked that Mr. Richardson somewhat

underrates the gravity of porter, which is now seldom under 20 lbs. per

barrel. The criterion for transferring from the gyle-tun to the

cleansing butts is the attenuation caused by the production of alcohol

in the beer: when that has fallen to 10 lbs. or 11 lbs., which it

usually does in 48 hours, the cleansing process is commenced. The heat

is at this time generally 75°, if it was pitched at 65°; for the heat

and the attenuation go hand in hand.

About thirty years ago, it was customary for the London brewers of

porter, to keep immense stocks of it for eighteen months or two years,

with the view of improving its quality. The beer was pumped from the

cleansing butts into store-vats, holding from twenty to twenty-five

gyles or brewings of several hundred barrels each. The store-vats had

commonly a capacity of 5000 or 6000 barrels; and a few were double, and

one was treble, this size. The porter, during its long repose in these

vats, became fine, and by obscure fermentation its saccharine mucilage

was nearly all converted into vinous liquor, and dissipated in carbonic

acid. Its hop-bitter was also in a great degree decomposed. _Good hard

beer_ was the boast of the day. This was sometimes softened by the

publican, by the addition of some mild new-brewed beer. Of late years,

the taste of the metropolis has undergone such a complete revolution in

this respect, that nothing but the mildest porter will now go down.

Hence, six weeks is a long period for beer to be kept in London; and

much of it is drunk when only a fortnight old. Ale is for the same

reason come greatly into vogue; and the two greatest porter houses,

Messrs. Barclay, Perkins, & Co., and Truman, Hanbury, & Co., have become

extensive and successful brewers of mild ale, to please the changed

palate of their customers.

We shall add a few observations upon the brewing of Scotch ale. This

beverage is characterised by its pale amber colour, and its mild

balsamic flavour. The bitterness of the hop is so mellowed with the

malt, as not to predominate. The ale of Preston Pans is, in fact, the

best substitute for wine which barley has hitherto produced. The low

temperature at which the Scotch brewer pitches his fermenting tun

restricts his labours to the colder months of the year. He does nothing

during four of the summer months. He is extremely nice in selecting his

malt and hops; the former being made from the best English barley, and

the latter being the growth of Farnham or East Kent. The yeast is

carefully looked after, and measured into the fermenting tun in the

proportion of one gallon to 240 gallons of wort.

Only one mash is made by the Scotch ale brewer, and that pretty strong;

but the malt is exhausted by eight or ten successive sprinklings of

liquor (hot water) over the goods (malt), which are termed in the

vernacular tongue, _sparges_. These waterings percolate through the malt

on the mash-tun bottom, and extract as much of the saccharine matter as

may be sufficient for the brewing. By this simple method much higher

specific gravities may be obtained than would be practicable by a second

mash. With malt, the infusion or saccharine fermentation of the

_diastase_ is finished with the first mash; and nothing remains but to

wash away from the goods the matter which that process has rendered

soluble. It will be found on trial that 20 barrels of wort drawn from a

certain quantity of malt, by two successive mashings, will not be so

rich in fermentable matter as 20 barrels extracted by ten successive

sparges of two barrels each. The grains always remain soaked with wort

like that just drawn off, and the total residual quantity is three

fourths of a barrel for every quarter of malt. The gravity of this

residual wort will on the first plan be equal to that of the second

mash; but on the second plan, it will be equal only to that of the tenth

sparge, and will be more attenuated in a very high geometrical ratio.

The only serious objection to the sparging system is the loss of time by

the successive drainages. A mash-tun with a steam jacket, promises to

suit the sparging system well; as it would keep up an uniform

temperature in the goods, without requiring them to be sparged with very

hot liquor.

The first part of the Scotch process seems of doubtful economy; for the

mash liquor is heated so high as 180°. After mashing for about half an

hour, or till every particle of the malt is thoroughly drenched, the tun

is covered, and the mixture left to infuse about three hours; it is then

drained off into the under-back, or preferably into the wort copper.

After this wort is run off, a quantity of liquor (water), at 180° of

heat, is sprinkled uniformly over the surface of the malt; being first

dashed on a perforated circular board, suspended horizontally over the

mash-tun, wherefrom it descends like a shower upon the whole of the

goods. The percolating wort is allowed to flow off, by three or more

small stopcocks round the circumference of the mash-tun, to insure the

equal diffusion of the liquor.

The first sparge being run off in the course of twenty minutes, another

similar one is affused; and thus in succession till the whole of the

drainage, when mixed with the first mash-wort, constitutes the density

adapted to the quality of the ale. Thus, the strong worts are prepared,

and the malt is exhausted either for table beer, or for a _return_, as

pointed out above. The last sparges are made 5° or 6° cooler than the

first.

The quantity of hops seldom exceeds four pounds to the quarter of malt.

The manner of boiling the worts is the same as that above described; but

the conduct of the fermentation is peculiar. The heat is pitched at 50°,

and the fermentation continues from a fortnight to three weeks. Were

three brewings made in the week, seven or eight working tuns would thus

be in constant action; and, as they are usually in one room, and some of

them at an _elevation_ of temperature of 15°, the apartment must be

propitious to fermentation, however low its heat may be at the

commencement. No more yeast is used than is indispensable: if a little

more be needed, it is made effective by rousing up the tuns twice a day

from the bottom.

When the progress of the attenuation becomes so slack as not to exceed

half a pound in the day, it is prudent to cleanse, otherwise the top

harm might re-enter the body of the beer, and it would become

_yeast-bitten_. When the ale is cleansed, the head, which has not been

disturbed for some days, is allowed to float on the surface till the

whole of the _then_ pure ale is drawn off into the casks. This top is

regarded as a sufficient preservative against the contact of the

atmosphere. The Scotch do not skim their tuns, as the London ale brewers

commonly do. The Scotch ale, when so cleansed, does not require to be

set upon close stillions. It throws off little or no yeast, because the

fermentation was nearly finished in the tun. The strength of the best

Scotch ale ranges between 32 and 44 pounds to the barrel; or it has a

specific gravity of from 1·088 to 1·122, according to the price at which

it is sold. In a good fermentation, seldom more than a fourth of the

original gravity of the wort remains at the period of the cleansing.

Between one third and one fourth is the usual degree of attenuation.

Scotch ale soon becomes fine, and is seldom racked for the home market.

The following table will show the progress of fermentation in a brewing

of good Scotch ale:--

20 barrels of mash-worts of 42-1/2 pounds gravity = 860·6

20 -- returns 6-1/10 = 122

-----

12 ) 982·6

-----

pounds weight of extract per quarter of malt = 81