The Difference of the Fermentation

—The greater or le rapidity with which the worts are made to ferment has a remarkable influence upon the quality of the beer, especially in reference to its fitne 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 di olved, 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 progre ive, and le 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 isingla . For porter, as commonly brewed, it is frequently had recourse to. A pound of good isingla 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 di olve. 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 di olves. 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 pa ing 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 le , according to the foulne 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 gla , we shall observe whether the feculencies begin to collect in flocky parcels, which slowly subside; or whether the isingla falls to the bottom without making any impre ion 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 isingla in the following way. The isingla , he thinks, is first of all rather diffused mechanically, than chemically di olved, 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 isingla , from subsiding. The beer is then properly enough called stubborn by the coopers. But the true theory of the action of isingla is, that the tannin of the hops combines with the fluid gelatine, and forms a flocculent ma , 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 | | Burton ale, 2d ditto | 35 | to | 40 | 1·097 to 1·111 | | Burton ale, 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 |