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it is not possible to regulate the distance between them, so as to prevent some of the grains from being ground to flour, while others escape almost untouched. Steel mills which cut the grains by means of teeth something like coffee mills are also used; they are preferable to mill-stones, but grind the malt too much. The best contrivance is a pair of case-hardened iron rollers, regulated at such a distance apart, that the grains in passing through them are bruised only, not cut or ground.
The water being heated to about 160° or 170° in a large copper, is drawn off into a mash tun situated at a lower level. When the water has cooled down to about lfi0° or under, a quantity of crashed malt is shaken in, sufficient to absorb nearly the whole of the water when thoroughly stirred up with long poles called oars, or by means of stirrers within the mash tun moved by machinery (Fig. 109). The quantity of water ought to be sufficient thoroughly to wet the malt, and
to cause it to swell considerably, so as completely to dissolve the sugar formed during the malting, and to allow the diastase to re-act upon the stareh, which until now has remained unchanged. It has even been recommended to use the first portion of water at so low a temperature as 140°, in order to prevent any thing like coagulation in the stareh. When the first water has thoroughly saturated the malt, and been left to repose for about hulf-an-hour, a second quantity of water at 194° may be introduced, and the mixture well stirred up. This mixture of water at 140° and 194°, forming a mean temperature of 167°, is most favourable for the action of the diastase. The mash tun should be covered up and left during two or three hours. The clear infusion of stceet wort as it is now called, is then drawn off into a vessel called an underback, situated at a lower level than the mash tun. This first infusion having carried off the greater portion of the sugar, and saccharified nearly all the
stareh; the temperature of the water for the next or second mash as it is called, may be as much as 194°. This, mingling with the cooled malt, is reduced to 176°. When this infusion is drawn off, it is added i o the first.
In the third mash, the water, which is near the boiling-point, removes all the remaining soluble matter, and leaves in the mash tun the ligneous pellicle or husk of the malt, a portion of coagulated albumen, and some foreign insoluble matters. This third infusion is not usually added to the first, but it is used for making small beer, or for wetting new malt.
The quantity of water employed for mashing depends, of course, on the greater or less strength of the worts. After the wort is drawn off, the malt retains about 32 gallons of water for every quarter of malt used. In the subsequent boiling and evaporation from the coolers 40 gallons of water are dissipated
for every quarter of malf, making 72 gallons loss of water in all; so that if 13 quarters of malt be taken to make 1,500 gallons of beer, 2,400 gallons of water will be required for mashing.
In order that the wort may flow off clear, the mash tun is furnished with a false bottom, raised a few inches above the ordinary wooden bottom of the vessel, and composed of metal plates, lying closely together, and fitting the tun perfectly all round. These plates are perforated with numerous funnelshaped holes, the widest part being downwards, and the hole in the upper surface too small to allow the grain to pass through. The cock for draining off the wort, or setting the tap as it is called, is placed in the tub between the two bottoms.
The first wort ought to be of the colour of the malt from which it is extracted; of a heavy sweet taste, and more delicate in flavour than the succeeding worts, because the water was not sufficiently hot to bring away the coarser and more disagreeable parts of the grain. On this account the first wort is sometimes reserved for superior ales, and the second and third for inferior beers.
In order that the brewer may be able to brew beer of the same quality, it is necessary for him so to regulate the strength of his worts, or in other words, the quantity of saccharine matter in the same measure of water, that they may be at all times identical. As the same weight of malt does not always afford the same quantity of sugar to the worts, he mingles the worts of the different mashes, according to certain proportions which are indicated to him by means of an instrument called a saccharomeler, which is one of the numerous forms of Hydrometer used in the arts. It consists of a hollow copper ball A, Fig. Ill, with a flat brass stem c d, and a weight a of the same metal attached to the foot stalk g h; the
weight a so adjusted that the instrument shall sink in distilled water at the temperature of 62° to the point b of the scale c b, which is divided into 10 equal parts. A barrel (36 gallons) of pure water at 62° weighs 360 lbs. avoirdupois, and the instrument is so regulated, that if put into a liquid weighing 361 lbs. per barrel, it would rise to the mark e. Each of the divisions between e and b will therefore represent tenths of a pound. A number of weights with holes in their centres, marked 1, 2,3, 4, 5,10, 20, and 30, accompany the instrument; these represent respectively pounds weight, and are placed as required on the top of the stem, and rest on the projection d. If, for example, in putting on the weight marked 10, the instrument sinks in a wort to the point b, a barrel of that wort at 62° would weigh exactly 10 lbs. more than a barrel of pure water. If the instrument cut the surface at two of the divisions below the point b, a barrel of the liquid would weigh 10.2 lbs. more than a barrel of water, or 370.2 lbs. But the brewer in speaking of his worts does not take into account the weight of the water; thus a barrel of wort weighing 370 lbs. is spoken of as a ten pound wort, and in this way all his caleulations are made. The following are examples:—
Barrels, lbs. gravity.
T.ic 1st wort 12 at 35 = 420
2d „ 14 at 20 = 280
3d „ 14 at 6 = 84
40 at 10.6 av. = 784 or 40 barrels of wort, which, if mixed together,
c, Fig. 112, is an assay jar, furnished with a cover B, and is used for containing the wort which is to be weighed by the saccharometer.
When the worts arc graduated to the proper strength, they are pumped from the underback as quickly as possible into the copper, which is usually a close vessel with a valve at the top (Fig. 110), loaded so that steam cannot escape at the temperature of 212°. The temperature therefore rises a little above this, when a portion of steam by its increased elasticity forces open the valve and escapes, while the temperature of the wort falls back to 212°. In this way the liquor is concentrated by boiling, and also made clear by the coagulation of the albumen of the barley, which the brewers term mucilage. The glutinous matter is also rendered insoluble by combining with the tannin of the hops. As soon as the wort is introduced into the copper, the proper proportion of hops is added, and the two are boiled together until the mixture becomes clear. It is necessary to keep the hops well stirred up during the boiling, to prevent them from settling at the bottom and burning. For this purpose a vertical rod passes into the copper through a stuffing box at the top. This rod terminates in a horizontal bar, carrying an extended chain called a rouser, and both are kept in motion by being connected with the moving machinery of the brewery. To prevent the loss of the volatile oil of the hops, a copper pan of water is placed at the top of the boiler, so arranged that the tube which permits the escape of steam and oily vapour passes both into the water, where they are condensed. The water thus impregnated is used in the next mashing.
The quantity of hops depends on the quality of the beer, the time of keeping, the season at which it is brewed, and the climate to which it is to be exported. A larger proportion of hops should be used in brewing in warm than in cold weather, and also if the beer is to be kept a long time or sent to a warm climate. The Kent and Sussex hop is strong and pungent, and is hence preferred by porter brewers; the Worcester hop, being milder and paler, is used for ales. For strong beer, i\ lbs. of hops to a quarter of malt is sometimes allowed. For the stronger kinds of ale and porter the rule is, in England, to allow 1 lb. of hops for every bushel of malt,
Fig. 113. THE COOLER.
shallow vessel of considerable area, nsually situated at the top of the brewery, and exposed on all sides to a current of air. The cooling ought to be as rapid as possible, to prevent acctification, or, as the brewers term it, foxing, for which purpose a horizontal fan, moving rapidly round, creates a powerful draught of air over the surface. A rapid cooling is sometimes effected by passing the wort through long pipes, which are surrounded by large quantities of cold water: this expedites the business of the brewery, and greatly diminishes the risk of foxing.
When the worts are cooled down to 55° or 600, and in some cases 63°, they are received into the fermenting tun, which is a vast circular vat or tub bound with strong iron hoops and covered in at all parts, except a hole which may be opened to inspect the process or to clean out the tun. A quantity of yeast is then added, varying with the strength of the wort and the season of the year; but in general, 1 gallon of yeast is sufficient to set 100 gallons of wort in complete fermentation. In warm weather the yeast is not added at once; but portions of the worts are let down from the coolers into the fermenting tun at different times, and a small portion of yeast is added each time. With large quantities of wort the temperature often rises very rapidly, and many precautions are required to prevent the fermentation from becoming unmanageable. For the scientific opinions respecting fermentation, we must refer to our article on that subject, but the phenomena of the process as it respects ale, are well described by Mr. Donovan:—" After the mixture of wort and yeast has been made some time, a frothy ring is observed leaving the sides of the tun, and proceeding a few inches towards the centre; and this is succeeded by another and another until at length the
whole surface is covered with a thin creamy froth. At the same time a hissing noise, or feeble effervescence is heard, owing to the breaking of innumerable air bubbles on the surface; and there is a small increase of volume, occasioned by involved carbonic acid. Meanwhile the froth rises higher; at first equally, and at length into abrupt elevations resembling rocks, as they are called by brewers. The colour of the froth at this period deepens: at first it was white; next it became yellow; and lastly, (although it is better if not,) it often becomes a brownish yellow. The froth is now highest in the middle of the tun, and the fermentation is at its maximum. At this time the froth has become more viscid; it holds the carbonic acid more obstinately involved; the bubbles break into each other and form large ones, which in their turn break, and occasion sndden subsidence in different parts of the foamy head. At length the whole head begins to flatten and subside; the middle part, which was the highest, becoming now the lowest; and the fermentation diminishes. The viscid head of yeast becomes more dense; and having parted with its gas, would soon fall down to the bottom of the tun if permitted; but at that period it is skimmed off, and the skimming repeated at intervals, as fast as yeast appears on it. This is done as well to lessen the fermentation as to remove a certain disagreeable bitterness, with which this first yeast is impregnated, and which there is a risk of returning to the wort, were it not now removed."'
During this vinous fermentation, a portion of the sugar of the wort is converted into aleohol. When the active fermentation is over, the head formed on the liquor in the tun would, if left to itself, subside; the effervescence would entirely cease; the liquor would become transparent; but after a short time a new set of changes would take place; the acetous fermentation would set in, and the conteuts of the vat would be converted into vinegar. [See Acetic Acid.] To prevent this, and at the same time to retain the aleohol, the aroma and bitter of the hop, and the carbonic acid in solution, and to cleanse the beer of the minute particles of yeast which are floating through it and rendering it mnddy, the beer is racked off into a number of vessels like hogsheads called the rounds (Fig. 114), in which the vinous fermentation is completed. A large quantity of carbonic acid is slowly liberated, which, attaching itself to the suspended particles of yeast, carries them up to the bung-hole, where both are expelled. The bung-hole of each cask is furnished with a sloping tray, which discharges the yeast into a wooden trough, in which the stillions stand (Fig. 114). These stillions are placed in communication with a store tub, which keeps the rounds always full, so that the head of yeast may pass freely over, and keep the body of the liquor in the cask clean.
When the fermentation is over, the beer is either pumped up from the rounds into immense store-vats (Fig. 115), some of which contain upwards of 1,500
(1) Cabinet Cyclopaedia. Domestic Economy, vol. i.
carriages, Src. The beer is never stationary in lis quality, even in the store vats; for as soon as it ceases to improve by the decomposition of its residuary sugar, it begius to degenerate into vinegar. In common strong ale or beer, the proportion of aleohol is about 4 per cent.; in the best brown stout, 6; in the strongest ale, 8; but in common beer, not more than 1 per cent. The nutritive properties of beer depend on its gum, sugar, and stareh-gum in solution. It also contains aromatic matters, lactic acid, different salts, and free carbonic acid, the latter varying from 2 to 25 or 26 per cent.
The cleansing is sometimes hastened by means of fining: that is, a solution of isinglass in weak sour beer, made from a fourth mash of the same malt, is put into every cask. It forms a kind of web over the surface of the liquor, and gradually sinking to the bottom, carries with it all the flocculent matter, and leaves the beer transparent.
We see, then, that by the process of fermentation the heavy wort has become transformed into a liquid now called beer or ale, of much less specific gravity, in consequence of the dense saccharine solution being partly transformed into a light spint. This process of attenuation, as it is called (from tenuis, thin), is carefully watched by the brewer, and measured by the saccharometer, by which means he can judge of the quantity of aleohol formed, and compare it with the amount of sugar which the same instrument indicated to him as present in the worts; he can thus determine the amount of unaltered sugar yet remaining in the beer as its food, and thus judge ol the time that it can be kept.
We will now, with the assistance of a diagram, briefly recapitulate the various processes of brewing on a large scale. Fig. 116 is the arrangement of a large porter brewery. The malt is hoisted up from the street by means of a crane, and is stored in spacious granaries or malt-lofts, M L, at the top of the building. Immediately below the granary is the mill M, for crushing the malt, and in the floor below are mill-stones, m s, for grinding the malt, when it is required to do so. The crushed or ground malt is conveyed by a trough into a chest, e, from which it is raised by the action of a„spiral screw into the large chest or bin, B, situated directly over the mash-tun, M T, into which it is let down as it is wanted. The water for the service of the brewery is obtained from the well w by a lifting-pump, worked by the steamengine s E; a foreing-pipe f of the pump conveys water up to the large cistern or water-back, w B, at the top of the engine-house. From this cistern iron pipes are laid to the copper p, and also to every part of the brewery where water is wanted for cleansing and washing the vessels. The copper p can be filled by turning a cock, and the water, when heated, is conveyed by the pipe p into the mash-tun M T. It is introduced beneath a perforated false bottom, upon which the malt lies, and, rising up through the holes, comes in contact with the malt. The copper is immediately refilled for a second mash. The wort from the malt is drained off into an underbaek, u b, situated immediately under the mash-ton, from which it is pumped into the copper p, or into a vessel situated above it, by means of the three-barrelled pump along a tube not shown in the diagram. When the water for the succeeding mashes is let out of the copper, the wort is introduced, with the proper proportion of hops, from the hop-loft h. When the boiling has continued a sufficient length of time, the contents of the copper are run off through a large cock into the jack-back, J, which has a perforated bottom to strain otf the hops. The hot wort is drawn off from the jack-back through the pipe a by the three-barrelied pump, which throws it up into the coolers, c, whii h are built in several stages, and open at the side, I y means of louvers, to the air. When the wort is sufficiently cooled, it is conducted in pipes from all th 3 different coolers to the large fermenling-vessel, F\, in which the first fermentation is conducted. From this vessel the beer is introduced into the rounds, n>
where the fermentation is completed, after which the beer is drawn off into immense store vats, where it is kept till wanted. The steam-engine, Se, which gives motion to the machinery, has attached to its large fly-wheel a bevelled cog-wheel, which turns another similar wheel upon the end of a horizontal shaft which extends from the engine-house to the great horsewheel, H w, which it turns by means of a cog-wheel. The horse-wheel puts in motion all the pinions for the mill-stones and rollers, the horizontal axis which works the three-barrelled pump, and the machinery within the mash-tun for agitating the malt. It also moves a sack-tackle for drawing up the sacks of malt and hops from the court-yard to t he top of the building. The hops are kept in their bags and pockets, but the malt is emptied out of the sacks into enormous bins. The horse-wheel, Hw, can be worked by horses, should the stcam-engine fail, which, however, is a rare occurrence.
In one of the breweries visited by the writer and Mr. W. H. Prior, who made the drawings for the engravings which illustrate this article, the quantity of malt wetted during the wintcr brewing season every Tuesday and Friday is 320 quarters, and on the four other days of the week 230 quarters. There were three coppers of the capacities of 350, 500, and 6OO barrels. The coal consumed per day is 10 or 12 tons, and the capacity of the largest store vat is equal to 1,568 barrels.
We have thus indicated the general processes of brewing as they are conducted in a London brewery. They are the same in principle wherever they are carried on. There are, however, variations in piactice or in the quality of the materials, in different districts, which afford characteristic differences in the product. The Scotch ale is justly celebrated for its mild flavour and pale colour, more resembling the pale wines of France than any other ales that are brewed in Great Britain, and, like them, it is the result of a lengthened fermentation. The low heat at which the tun is pitched confines the brewing to the colder part of the
year, all operations being suspended in the summer months. The Edinburgh brewer is particularly careful in the choice of his malt, and hops, and yeast. He only makes one mash for strong ale, and completes his quantity or length of wort by eight or ten subsequent sprinklings or spargea of liquor over the goods. These sparges trickle in succession through the malt, and wash out as much more of the saccharine from the mash as may suffice for the intended strength of the ale. The mashing is begun with water at ]80° or even 190°, and after working up the malt for half an hour, the whole is covered up, and allowed to infuse about three hours, when it is drained off into the underback. Water at 180° is then sprinkled equidly over the goods by being poured upon a cireular board swung over the centre of the mash-tun, and, being perforated with small holes, the water descends in a shower. Three or four stop-cocks are inserted in different parts of the bottom of the tun, for drawing off the liquor, in order that it may permeate every part of the goods equally. When the first sparge is nm off, whieh maj be in 20 or 25 minutes, a second