CHEMICAL EXAMINATION OF RAW MATERIALS. 197 



ferment, and immediately removing them. By proceeding in 

 this manner, the entire surface will in a few hours be covered 

 with vinegar ferment, when there will be no further danger of 

 the dislodgment of the latter by mold ferment. 



The process of acetification being finished, the vinegar is drawn 

 off into storage barrels, which must be kept full up to the bung, 

 and subjected to the same treatment as the product obtained from 

 wine. 



CHAPTER XIX. 



CHEMICAL EXAMINATION OF THE RAW MATERIALS AND CON- 

 TROL OF THE OPERATIONS IN A VINEGAR FACTORY. 



Determination of Sugar. 



THE sacchariferous materials used by the vinegar manufacturer 

 are either whiskey-mashes, malt-extracts, or must prepared from 

 wine-lees, apples, etc. The determination of sugar contained in 

 these fluids is effected by means of various instruments, which 

 are really hydrometers, with different names and graduations. 

 The instruments mostly used for the determination of sugar in 

 whiskey-mashes and malt-worts are known as saccharometers, 

 and directly indicate the content of sugar in the fluid in per cent: 

 A similar instrument, known as the must-aerometer, serves for 

 the determination of the content of sugar in grape-must. Ac- 

 cording to the arrangement of their scales, the must-aerometers 

 indicate either direct sugar per cent., or degrees ; in the latter 

 case the use of special tables accompanying the instrument is re- 

 quired for finding the per cent, of sugar corresponding to a cer- 

 tain number of degrees. 



No special saccharometer for fruit-must having as yet been 

 constructed, the determination of the content of sugar has to be 

 effected either by a tedious method unsuitable for practice, or, 

 what can be more quickly done, by fermenting a sample of the 

 respective must, and after determining the quantity of alcohol, 

 ascertaining from it the content of sugar. 



