Page:A Practical Treatise on Brewing (4th ed.).djvu/220

204 to admit such high temperatures as to be carrying on what is called the acetous instead of the vinous fermentation. It is still disputed, and must always remain a delicate question among chemists, at what temperature the acetous fermentation commences; but at or under 75°, or, perhaps, even a few degrees higher, little or no risk can be run; it is, therefore, desirable to keep within the limit of 75°. In all cases of this kind, therefore, the proper temperature at which the worts must be got together in the fermenting tun, must depend on such circumstances as can only be judged of by the brewer.

Let us suppose that the worts, when placed in the fermenting tun, are at a medium temperature, or at 58°: thus leaving opportunity for an increase in temperature of 18 or 19 degrees before cleansing or tunning. Let a sufficient quantity of good, sound, lively yeast, be procured, and when the worts in the coolers fall to a temperature of 70°, mix two pounds of the said yeast with a little of the worts at that temperature, contained in a pail. As soon as the mixture begins to rise, let 10 gallons of the worts run into your fermenting tun, into which throw your yeast so rising. This is called pitching. Rouse it about until it is thoroughly mixed; then take six pounds more of the same yeast, and mix it with worts in a pail as before-directed, so as to let it begin to rise in the pail before using. If it begin to ﬂow over the pail before the worts have arrived