Page:A Practical Treatise on Brewing (4th ed.).djvu/133

Rh It is well known, and can easily be shown, that positive electricity excites acidity in worts or beer, while negative electricity prevents it. This accounts for the tendency to acidity in all beer which has been subjected to positive electro-chemical action in any part of the process of brewing, but particularly in the gyle-tuns during fermentation.

From what has been said it would appear that there must be some doubt as to whether what is called the acetous fermentation has ever as yet been properly deﬁned; and, with all due deference to much higher authority, it seems at least very doubtful whether the term acetous fermentation is scientifically applicable to any stage of the process of converting beer into vinegar. At all events, no undue acidity takes place in the prior vinous fermentation, unless produced by galvanic action or other accidental causes.

In confirmation of the above, it may be stated, that distillers in the fermentation of their wash wish to avoid all acidity as much as brewers. It decreases the quantity of spirits from the still in proportion to the extent of acidification which may have been generated. Their fermentations, however, generally speaking, are carried on at as high temperatures, or nearly so, as those used by the vinegar-makers; but when successfully