Old hock requires the same proportion of hops as are used in keeping pale strong, or keeping pale small beer; but more or less, according to the time it is intended to be kept before it becomes fit for use. The length is about two barrels, from a quarter of the palest and best malt. As spontaneous pellucidity is required, its whole medium must not exceed 138 degrees, for the drying and extracting heat. The management of it, when fermenting, is under the same rules with keeping small beer, or those which are allowed a due time to become of themselves pellucid.
Dorchester beers, both strong and small, range under the same head. They are brewed from barleys well germinated, but not dried to the denomination of malt. The rule of the whole 138 degrees for the governing medium, must, even with this grain, be observed to form these drinks; but, from the slackness of the malt, and the quantities of salt and wheaten flour mixed with the liquor, when under fermentation, proceed its peculiar taste, its mantling, and its frothy property.
SECTION IV.
OF THE NATURE AND PROPERTIES OF HOPS.
The constituent parts of malt, like those of all vegetable sweets, are so inclined to fermentation, that, when once put in motion, it is difficult to retard their progress, retain their preservative qualities, and prevent their becoming acid. Among the many means put in practice, to check this forwardness of the malt, none promised so much success as blending with the extracts, the juices of such vegetables as, of themselves, are not easily brought to fermentation. Hops were selected for this purpose, and experience has confirmed their wholesomeness and efficacy.
Hops are an aromatic, grateful bitter, endued with an austere and astringent quality, and guarded by a strong resinous oil. The aromatic parts are volatile, and disengage themselves from the plant with a small heat. To preserve them, in the processes of brewing, the hops should be put into the copper as soon as possible, and be thoroughly wetted with the first extract, while the heat of the wort is at the least, and the fire under the copper has little or no effect thereon. Whoever will be at the trouble to see this performed, by the means of rakes, or otherwise, will be made sensible, that flavor is retained, which, when the wort comes to boil, is otherwise constantly dissipated in the air.
The bitter is of a middle nature, or semivolatile: it requires more fire to extract it, than the aromatic part, but not so much as the austere or astringent. Hence it is plain, that the principal virtues of this plant are best obtained by decoction, the austere parts not exhibiting themselves, but when urged by so violent and long continued boiling, as is seldom, or never practised in the brewery. It would be greatly satisfactory to fix, from experiments, the degrees of heat, that first disperse the aromatic, next the bitter, and lastly the austere parts; as it is likely, by this means, a more easy and certain method of judging of the true value and condition of hops, than any yet known, might be discovered.
This vegetable is so far from being, by itself, capable of a regular and perfect fermentation, that, on the contrary, its resinous parts retard the aptness which malt has to this act. Hops, from hence, keep barley-wines sound a longer space of time, and, by repeated and slow frettings, give an opportunity to the particles of the liquor to be more separated and comminuted. Fermented liquors acquire, by this means, a greater pungency, even though it was admitted they received no additional strength from this mixture, the direct contrary of which might easily be made to appear. Hops, then, are not only the occasion of an improvement of taste, but an increase of strength.
Dr. Grew seems to think the bitter of the hops may be increased by a greater degree of dryness; but, perhaps, this is only one of the means of their retaining longer this quality, which undoubtedly decreases through age, in a proportion, as near as can be guessed, of from 10 to 15 per cent. yearly.