THE MICROBIOLOGY OF ALCOHOL PRODUCTS 533 



PoMBE is a kind of beer made in Africa from millet seed by sprouting 

 to sacchaxify the starch and subsequent spontaneous fermentation in 

 water. It is interesting as the source of the genus Schizosaccharomyces 

 which appears to take the main part in the fermentation. 



Ginger beer is an acid, slightly alcoholic beverage made by the 

 fermentation of a 10 to 20 per cent solution of sugar containing a few 

 pieces of ginger root. The fermentation is induced by adding small 

 pieces of the so-called ginger-beer plant which consists of Bad. vermi- 

 jorme and S. pyriformis. The bacteria form a thick gelatinous sheath 

 and seem to live symbiotically with the yeast, each developing best 

 in the presence of the other. 



DISTILLED ALCOHOL 



Introduction 



Uses and Sources of Alcohol. — Distilled alcohol is used as a 

 beverage and a medicine or for innumerable purposes in the arts and 

 industries. Certain methods and sources employed for the latter pur- 

 poses are inadmissible for the former. 



In all cases, it is made by the preparation from saccharine or starchy 

 substances of a sugar solution suitable for the work of yeast, the 

 fermentation of this solution, and, finally, the distUlation of the alcoholic 

 liquid. 



AVhere the raw materials are sugary, methods similar to those of 

 wine-making, and where starchy, to those of brewing, are employed, 

 modified to suit the conditions of each case. 



The principal potable alcohols are brandy, made from grapes, rum 

 from sugar cane, and whiskey from rye or other grains. Many other 

 sources are used and any fermented beverage will, by distillation 

 produce a potable spirit varying in character and quality with the 

 source. Industrial alcohol may be made from any substance capable of 

 undergoing alcoholic fermentation, the Umiting factor in practice being, 

 principally, the cost of the raw material per unit of alcohol. 



Methods 



Preparation or the Sugar Solvtion.— Saccharine Raw Materials. 

 — When spirits are to be made from grapes or other fruit, the juice is fer- 



