198 VINEGAR, CIDER, AND FRUIT-WINES. 



Iii place of special saccharometers or must -aerometers, an ordi- 

 nary aerometer indicating the specific gravity can also be used, 

 and the content of sugar corresponding to a certain specific grav- 

 ity found from a reducing table. Tables X. to XIII. at the end 

 of this volume give the content of sugar especially for wine-must, 

 but also with sufficient accuracy for apple- or pear-must, accord- 

 ing to the statements of the respective must-aerometers. 



Determination of Alcohol. 



In a factory using commercial spirits of wine as the fundamen- 

 tal material for the fabrication of vinegar, the percentage of ab- 

 solute alcohol contained in it has to be accurately determined in 

 order to enable one to correctly calculate, in the manner ex- 

 plained on p. 104, the quantity of water required for the prepa- 

 ration of alcoholic liquid of determined strength. 



For the determination of the content of alcohol in pure spirits 

 of wine consisting only of water and alcohol, instruments called 

 alcoholometers are generally used ; they indicate the volumes of 

 alcohol contained in 100 volumes of the spirits of wine. They 

 are, however, not suited for this purpose when, as is frequently 

 the case in a vinegar factory, the spirit of wine contains other 

 bodies besides water and alcohol. In this case, either the alcohol 

 contained in a sample has to be distilled off, and after determin- 

 ing its strength by the alcoholometer, the content of alcohol in 

 the total quantity of fluid ascertained by calculation, or the de- 

 termination is effected in a short time and with sufficient accuracy 

 for practical purposes by the use of a special apparatus. 



Determination of the Alcohol with the Alcoholometer. 



For the vinegar manufacturer the alcoholometer is an import- 

 ant instrument in so far as it serves for quickly ascertaining the 

 degrees of the spirits of wine used. It is best to use an in- 

 strument which is combined with a thermometer, one being thus 

 enabled to ascertain the temperature of the fluid simultaneously 

 with reading off the statement of the alcoholometer. Tables I. 

 to VIII. appended to this work give the necessary assistance for 



