CHAPTER XLVIII 

 BACTERIAL DISEASES OF FERMENTED LIQUORS 



The transformation of sugar into alcohol is a phenom- 

 enon that was well known to the ancients. From time 

 immemorial, advantage has .been taken of this knowledge 

 for the preparation of a great many fermented liquors. 

 The organisms chiefly concerned in the alcohoHc fer- 

 mentation of sugar are yeasts, and not bacteria, although 

 the ability to produce alcohol is more or less common, 

 also, to bacteria and molds. It is beyond the scope of 

 the present work, therefore, to treat of alcoholic fer- 

 mentations, even though they be of considerable interest 

 to agriculture in their relation to grapes, grain, potatoes, 

 and other raw materials of the fermentation industries. 



The "turning" of wine and beer. — There are some 

 changes, so-called diseases, to which wine, beer, cider, 

 and other alcoholic beverages, are subject. The manu- 

 facture of vinegar, like these, is due to, or dependent 

 upon, bacterial activities. The turning of wine and beer 

 may be occasioned by acetic ferments, or by lactic fer- 

 ments. The lactic taint appears most frequently in wine 

 that is still young. The wine becomes turbid, acquires 

 an irritating taste or flavor, and may subsequetitly 

 be changed to a brown or black liquid. A slimy precipi- 

 tate is formed and gradually accumulates at the bottom 



(458) 



