INTRODUCTION. So many treatises on Brewing, both theoretical and practical, have already appeared, that the subject may very naturally be considered to have been exhausted. Some of these productions, however, are too homely; while others so abound with scientific technicalities, as to be altogether unintelligible to the general reader. That Brewing is a chemical process, no one can deny, and of course, in every work on the subject, some chemical terms must be used. In the following pages, however, it is not intended to give any account of the production or nature of gases or other chemical agents, further than may be absolutely requisite to elucidate the subject. Nor is it intended to introduce a history of the origin of Beer, which must in a great measure be conjectural. In most arts, such as dyeing, iron-making, calicoprinting, glass-making, &c., great improvements have been introduced by the assistance of chemis B try; while the art of Brewing, which may be considered equally important, has remained, to say the least, stationary. This may be easily accounted for. It is well known that many eminent chemists have turned their attention to this subject, and would no doubt have made as great improvements in it, as they have done in other arts, had they been furnished with the same advantages in regard to practical information. This, however, unfortunately has not been the case; for practical brewers, generally speaking, either from self-sufficiency, jealousy, or ignorance, are very unwilling to impart their real or supposed information to any one; but particularly to men of science, whose inquiries excite their jealousy. This, in many instances, prompts them rather to mislead than to inform the inquirers. Another obstacle to improvement is, that almost every brewer in the course of his practice, persuades himself that he has made some discovery, by which he can make his beer better than that of his neighbour. These nostrums, though often worse than useless to the possessors, might, if freely communicated to scientific inquirers, lead to some improvement; but they are invariably concealed, and thus the want of the combination of science with practice, throws insurmountable difficulties in the way of acquiring useful and accurate information. Had it been otherwise, there can be no doubt, that the Art of Brewing would have been long ago placed, by the assistance of chemistry, on a more scientific footing. Having had occasion, in the course of a connection of more than forty years with the brewery, to work in premises very differently constructed, we have invariably found, that in each some cause existed which prevented uniformity in the process of fermentation; and until that cause, whatever it might be, was traced and removed, no regular system could be introduced. This sufficiently shows why brewers who go from one brewery to another, cannot arrive at the same successful results with regard to the quality of the beer, although they pursue precisely the same system, and even on some occasions employ the same materials as before. They are thus, from want of chemical knowledge, left completely in the dark, without the possibility of tracing causes and effects. This shows the absolute necessity of applying the discoveries of chemistry, as in other arts, to account for and rectify these anomalies, which without such aid cannot be effected. The principal object of the following treatise is to trace the causes of these anomalies, and as far as possible to point out the means of removing or rectifying them; and on all occasions to advance only such opinions as are founded on principles strictly chemical and practical, without which, in the |