160 VINEGAR, CIDER, AND FRUIT- WINES. 



The purpose of this operation is to render all ferments present in 

 the mash ineffective. Lactic acid ferment and frequently also 

 butyric acid ferment always adhere to the malt, and, if allowed to 

 develop in the mash, would form lactic and butyric acids during 

 fermentation which would be injurious to the process of alco- 

 holic fermentation as well as to the properties of the vinegar to 

 be manufactured. The mash is now reduced to a temperature of 

 about 57 or 59 F. by bringing it into the cooling-back or pass- 

 ing it through a system of refrigerating pipes. ' When working 

 on a small scale the mash can be suitably cooled by allowing cold 

 water to pass through a coil placed in the vat containing it. 



The strength of the vinegar to be manufactured depends on 

 the concentration of the mash ; mashes showing a saccharometer 

 statement of 20 per cent, contain after fermentation about 9J per 

 cent, of alcohol which yields vinegar of about 8 per cent. ; mashes 

 showing 18 per cent, yield vinegar of about 7 per cent., so that 1 

 per cent, of acetic acid in the vinegar may be calculated on for 

 about every 2J degrees indicated by the saccharometer. 



The mash is now set with yeast, though the latter may be added 

 when the mash still shows a temperature of 71.5 to 75 F., the 

 yeast having then time to vigorously augment. Mashes prepared 

 from malt alone are uncommonly rich in nourishing substances 

 for the yeast, the latter augmenting abundantly and inducing a 

 very vigorous process of fermentation. This can be profitably 

 utilized by combining the manufacture of vinegar and that of 

 compressed yeast, a valuable product being thus obtained without 

 any extra expense and with but little labor. At a certain stage 

 of the alcoholic fermentation the yeast comes to the surface of the 

 fluid and can be lifted off. By washing the yeast once or twice 

 with cold water and then freeing it from the excess of water by 

 pressing, compressed yeast is obtained which, with the exception 

 of the portion to be used for setting fresh mashes, can be sold. 



Up to the completion of alcoholic fermentation the treatment 

 of the mash, as can be seen from tho preceding description, does 

 not essentially differ from that to which mashes for the manufac- 

 ture of alcohol are subjected. If, however, the completely fer- 

 mented "ripe" mash is to be used for the fabrication of vinegar, 



