Cooling is one of the most interesting, as it is one of the most important, phases of brewing. The manner in which it is accomplished in model breweries of to-day, impresses us with the greatness of science and its illimitable resources when pressed into service of a progressive industry. Formerly, the successful brewer of lager-beer depended very much upon the climate, the supply of ice and the chances of securing what the Germans style “Felsenkeller,” rock cellars; that is, deep caverns hewn into the rocks. The refrigerators of to-day completely emancipate the brewer from the thraldom of these contingencies; he can now brew almost anywhere and everywhere, even in Southern climates. Mild winters and consequent scarcity of ice have no terrors for him; and if it were not for his second nature to utilize every natural advantage offered him, he might get along without any cellars, certainly without “Felsenkeller.” From the cooling-tank the wort is conveyed through pipes into a pan, whence it trickles over two refrigerators. These two refrigerators are on separate floors, one above the other; the one over which the wort passes first is supplied with water from an artesian well; the other derives its cooling capacity from a refrigerating plant, of which we shall presently speak at some length. Having now reached the temperature most suitable for the beginning of fermentation, the wort passes directly into the fermenting tuns.
FERMENTATION
Fermentation, artificially induced by the admixture of yeast, at the rate of about one pound per barrel, sets in at once and gradually converts the saccharine principle into alcohol and carbonic acid gas, thus imparting to beer that quality which places malt liquors in the category of intoxicating beverages.
While fermentation continues, the same vigilance which prevails in every part of the brewery, must be constantly exercised. The conversion of sugar into alcohol and carbonic acid gas should be gradual, not sudden; hence, when the fermenting process becomes too rapid, either by reason of defective yeast or on account of the unsuitable temperature, it must be restrained by means of attemperators, that is, coils which are placed in the fermenting-tun and connected with the refrigerating plant.
As in all other operations thus far described, so here, too, the prolific genius of our age of inventions has placed at the command of the brewer machineries with which he can regulate the temperature of these oceans of turbulent, foaming liquids, either by a light pressure of his hand, by the turning of a small wheel, by pressing upon a knob, or by such other equally simple manipulation. In this fermenting room, as well as in the cellars, into which we shall pass presently, everything assumes Titanic proportions, and the human beings who move about these places appear like pigmies. When we see fermenting-tuns holding from three hundred to four hundred barrels, and settling tuns of the size of an ordinary house, extending through two stories, and holding seven hundred barrels or twenty-one thousand seven hundred gallons of beer; and when we consider that these monster casks, filled with John Barleycorn’s blood, cover miles upon miles of cellar-room, we begin to realize and appreciate the power of the engines which are at work in this brewery.
As fermentation progresses, workmen are constantly in attendance to watch the process. On ladders, almost three times the size of their own bodies, they climb to the top of the tuns to skim the beer with huge ladles, testing at the same time, by taste and touch, the condition of the liquid mass, in order to determine when to draw it off to the resting-tuns.
The transfer of the beer from the fermentation vats to the resting-tuns and from these to the storage casks is accomplished by hydraulic and air pressure, and in such a way as to require no other labor but that of opening or closing valves or depressing levers. As we descend into the cellars, three stories under the ground, the temperature becomes more and more stinging, the walls and ceiling are covered with ice to the depth of from three to five inches, and every vat and cask is thickly encrusted with frost. In forming an idea of the capacity of these cellars, we cannot simply depend upon the number of square feet of ground occupied by them, because both vats and casks rise to a height almost equal to that of the cellars, and they vary in capacity from fifty to five hundred barrels. The beer contained in them would float a fleet, since their aggregate minimum capacity amounts to 125,000 barrels.
FINAL
OPERATIONS
The last operations to which the beer is subjected are those of cleansing, fining and krausening. The beer passes from the settling vats to the storage casks, in which it remains from three to four months, when, after another winding journey through miles of pipes, it emerges bright and clear and brilliant, only to be racked, that is to say, filled into kegs which go to the retailers.
The same continuity of operations which we have witnessed on the floors above ground, is also observed in the three tiers of cellars, and the relation between the latter is almost as close as that between the former. We have already indicated the character of the connection which exists between the different kinds of tuns, vats and casks into which the beer is filled at different stages after the brew is completed. We have seen that fermentation takes place in open vats, and is regulated by attemperators, fed by the refrigerating plant and by means of powerful pumps. Formerly, another means of restraining fermentation, which was applied manually, was resorted to; it consisted of conical cans, called swimmers, which the brewer filled with ice and placed in the fermenting liquid, where they floated about and depressed the temperature.