Most brewers’ coppers, though they vary in their dimensions, are generally made in proportions nearly uniform; the effect of one inch of cold water more or less, will therefore nearly answer alike, that is, it will alter the heat of the tap, by 4 degrees. But this will only hold good in such cases, where the water is in the same proportion to the volume of the grist. In brewing brown beers, or porter, three worts are generally made; the extracts therefore must be of different lengths from what they are in beers brewed at two worts only. In this case, the quantity of water for the first wort, is less than it otherwise would be; and what must be allowed for the first mash, to wet the malt, is so much as to occasion the second, or piece liquor, to be proportionably less also; as it is of great consequence, if the first tap doth not answer to its proper degree, that the second should be brought to such a heat, as to make up the medium of the first and second extracts, the second, or piece liquor, by reason of its shortness, is more conveniently, and more exactly tempered in the little copper; and one inch cooling in, is in this case found, both by calculation and experience, to occasion a difference of one degree of heat only in the mash. One of the principal attentions, in forming beers and ales of any sort whatever, is that they may come to their most perfect state, at the time they are intended to be used. Common small beer is required to be in order, from one to four weeks, and as it is impossible to prejudge the accidental variations, as to heat and cold, that may happen in any one season of the year, it is rational to act up to what a long experience has shown, is to be expected, and to mix such quantity of cold water with that, which is made to come to ebullition, as to bring the extract to the degree fixed for each particular season, let the heat, at the time of brewing, vary therefrom, in any degree whatever. In treating on the subject of air, in the former part of this work, I observed the effect it had in penetrating the parts of the malt, or in the technical term used by brewers, in slacking it. As such is the case, when the grain is entire and whole, it is more so when ground, and experience teaches us, that, when malt has been about 24 hours from the mill, the dampness it has imbibed is equal to half an inch more of cold water added to that which is to be made to boil for the first liquor, and produces therefore a diminution of 4 degrees in the heat of the tap[11]. An effect, somewhat resembling this, is caused by the impression of the air on the utensils of a brewhouse, which are not daily used; the heat received from a foregoing process has expanded their pores, and rendered them more susceptible of cold and moisture. From this circumstance, the heat of the first mash will be affected in a proportion equal to half an inch less cooling in, or in the space of 24 hours, to 4 degrees of heat.