104 VINEGAR, CIDER, AND FRUIT-WINES. 



CHAPTER XL 



PREPARATION OF THE ALCOHOLIC LIQUID. 



UNDER the term " alcoholic liquid" is to be understood every 

 fluid to be converted into vinegar which, besides water and small 

 quantities of nourishing salts and albuminous substances, does 

 not contain over 14 per cent, of alcohol. In the directions 

 generally given for the preparation of such liquids vinegar is 

 mentioned as an indispensable constituent. While it cannot be 

 denied that a content of vinegar in the alcoholic liquid exerts a 

 favorable effect upon the formation of vinegar, it must be ex- 

 plicitly stated that it is not the acetic acid in the vinegar, which 

 in this case becomes active, but the ferment contained in it. 



In a vinegar factory vinegar just finished and entirely turbid 

 is always used for the preparation of alcoholic liquid, and a 

 microscopical examination shows such vinegar to contain in- 

 numerable germs of vinegar ferment. This ferment on coming 

 in contact with much air in the generators will evidently increase 

 rapidly and contribute to the quick acetification of the alcohol. 

 That it is actually the ferment in the vinegar used which exerts 

 a favorable effect can be shown by a simple experiment. By 

 adding vinegar previously heated to from 140 to 158 F. to the 

 alcoholic liquid the formation of vinegar in the generators pro- 

 ceeds more slowly, the ferment contained in the vinegar having 

 been killed. 



The best proof, however, that the alcoholic liquid does not re- 

 quire any considerable quantity of acetic acid for its conversion 

 into vinegar is furnished by the behavior of wine. Correctly 

 prepared wine of a normal composition contains only a few ten 

 thousands of its weight of acetic acid, and this must very likely 

 be considered as a product of vinous fermentation. If such wine 

 be stored for years in a cool cellar, its content of acetic acid does 

 not change. By, however, exposing such wine in a shallow 



