The Theory and Practice of Brewing

by Michael Combrune

The varieties of the soils in which hops are planted, may have some share in the inequality we perceive in them. They seem to be much benefited by the sea air. Whoever will try similar processes with the[19] Worcestershire and Kentish hops, will soon perceive the difference, and the general opinion strengthens this assertion, as the county of Kent alone produces nearly half the quantity of hops used in this kingdom.

The sooner and the tighter hops are strained, after having been bagged, the better will they preserve themselves. The opinion that they increase in weight, if not strained until after Christmas, may be true, but will not recommend the practice; the hops imbibe the moisture of the winter air, which, when the weather grows drier, is lost again, together with some of the more spiritous parts. Nor is this the greatest damage occasioned by this delay, as hops, by being kept slack bagged in a damp season, too often become mouldy.

Hops may be divided into ordinary and strong, and into old and new. The denomination of old is first given to them, one year after they have been bagged. New ordinary hops, when of equal dryness, are supposed to be nearly alike in quality, with old strong ones.

The different teints, with which hops are affected from the fire of the kiln, afford in brewing the best rule for adapting their color to that of the malt; in general the finest hops are the least, but the most carefully, dried.

To extract the resinous parts of the hops, it is necessary they should be boiled. The method of disposing them is generally to put the whole quantity, in the first wort, which, being always made with waters less hot than the succeeding extracts, possesses the greatest share of acids, and is in want of the largest proportion of resins and bitters to defend it. The virtue of the hops is not entirely lost by once boiling, there remains still enough to bitter and preserve the second wort. But where the first wort is short of itself, and a large quantity of hops are required for the whole, it is needless and wasteful to put more in at once than it can absorb, the overplus of which appears by a thin bitter pellicle floating on the wort when laid to cool in the backs. No particular rules can be given to avoid this inconveniency, as the nature and quantity of the worts on one side, and the strength of the hops on the other, must occasion a difference in the management, easily determinable by experience.

When waters, not sufficiently hot, have been used, the wort, for want of the proper quantity of oils, readily admits of the external impressions of the air, and is easily excited to a strong and tumultuous fermentation, which disperses the bitter particles, and diminishes the effects of the hops. The virtue of this plant is therefore retained in the drinks, in proportion to the heat of the extracts, and the slowness of the fermentation.

But beers being a composition of malt, hops, and water, united by heat, and the properties of this combination being judged of by the medium of the whole number of degrees of fire made use of in the process, as we brought the virtues of malt to this denomination, it is also essential to reduce those of hops. After many tedious calculations and experiments, made with this view, and unnecessary here to mention, we were obliged to have recourse to a more simple and probable hypothesis, and confirm the truth thereof by repeated experiments, the relation of which, as it becomes here necessary, will shew the necessity we were under to take a general view of the whole process before we attempted to ascertain this point.

In the table shewing the mean heat of the air applicable to practice, the greatest cold is 35 degrees, and in this season we observed, (page 156) the repositories of beers were more warm than this by 10 degrees, which makes the greatest cold of cellars to be 45 degrees; in the same table the highest heat is 60, when cellars are 5 degrees colder than the external airs, the utmost difference then in the temperature of cellars is 10 degrees, and this takes place in 6 months, so that the whole variety of heat beers deposited for keeping undergo in one twelvemonth is 20 degrees.

There is no specie of beer, in brewing of which it is requisite the artist should be more attentive to alter his process in proportion to the change of heat in the air, than common small beer, which, though brewed in every season, is constantly expected to be in an uniform order for use. In the preceding section, in the table directing this variety, we find a difference of five degrees of heat in the air, requires an alteration in medium heat of the whole process of 3 degrees, and as it is from the mean heat of the dryness of the malt, of the heat of the extracts, and of the value of hops in degrees, that we are to discover the quantity of fire to be given to the extracts, this can be done only by deducting from such medium so much as it is affected by the properties of the hops. Just before we have seen, that the whole of the variety of heat beers deposited in cellars to keep twelve months undergo, amounts to 20 degrees, these, in a proportion of 5 to 3, would be 12, without being scrupulously exact. Hops, with regard to their proportion in the whole process, must be admitted to be one third part thereof, and, in this case, of the proportion, 12, now found, only 4 degrees would be what they contribute towards preserving the drink 12 months: the quantity of hops necessary to maintain beers in a sound state this space of time, we have found to be twelve pounds; this quantity then is equal to 4 degrees of the medium heat of the whole process. On these grounds we repeatedly tried the experiment in a variety of brewings made for different purposes, and never found any inconveniencies from the estimating hops in such like proportion.

Hops should be used in proportion to the time the liquors are intended to be kept, and to the heat of the air in which they are fermented. The quantity requisite to preserve beers twelve months, experience has shewn to be[20]twelve pounds, of a good quality, joined to one quarter of malt, and when the heat of the air is at 40 degrees, three pounds to every quarter has been found sufficient to preserve drinks from four to six weeks, as six pounds are to keep them the same term when the thermometer is so high as 60 degrees. From these facts, founded on informations obtained from long practice, we shall hereafter ascertain the proper quantities to be used in all cases.