532 MICROBIOLOGY OF SPECIAL INDUSTRIES 



The same results may be obtained by mixing from 20 to 50 per cent 

 of grape must or apple juice with the diluted honey. 



Miscellaneous Fermented Beverages 



Fermented beverages of some kind are made in practically every 

 part of the world. They are very numerous and varied but fall natur- 

 ally into three groups; those made from the sweet juices of fruits or 

 other plants in which the methods of manufacture resemble those of 

 wine making; those made from starchy materials in which the methods 

 resemble those of brewing; and finally those made from the milk of 

 cows or other mammals which are discussed in Chapter IV, Div. IV. 



Belonging to the first group are numerous beverages made from 

 the juices of sugar cane, various palms, and tropical fruits. The best 

 known of these is the Mexican Pulque made by the spontaneous 

 fermentation of the sweet juice of the agave. Little is known about the 

 microflora concerned, but it includes alcohol-forming organisms which 

 prpduce about 6 per cent of alcohol, and bacteria which cause rapid 

 deterioration and spoiling of the fermented product. The pulque is 

 ready for consumption twenty-fours hours after the commencement of 

 fermentation arid cannot be kept more than a day or two. 



Of the beverages produced from starchy materials the Japanese Sake, 

 Rice Beer, has been most studied. It is made from rice by the 

 diastatic action of Aspergillus oryzcB and yeast fermentation. The 

 process includes three stages. First the preparation of koji which 

 consists of steamed rice on which the spores of the fungus are sown 

 and allowed to grow at 20° until the whole mass is penetrated with 

 mycelium. The next stage is the preparation of moto which is a thick 

 liquid consisting of steamed rice, water and koji in which the fungus 

 transforms the starch into sugar at 0° to 10° in a few days. Fermen- 

 tation then starts spontaneously, alcohol being produced by the action 

 of several yeasts and lactic acid by bacteria, both present accidentally. 

 In about two weeks the moto is ready. The last stage is the principal 

 fermentation which occurs on mixing together steamed rice, koji, moto 

 and water. This requires two weeks. The liquid is then separated, 

 cleared and stored. It contains a considerable amount of alcohol and 

 and can be kept and aged like wine. Sake is said to average 18 per 

 cent of alcohol and may reach 24 per cent, the highest alcohol content 

 known to be produced by fermentation. 



