YEASTS AND MOLDS 



301 



is in turn converted into alcohol by the Saccharomyces. If the fermenta- 

 tion product (as grape wine, apple cider, beer, porter, etc.) is exposed to 

 the air for a time, the Mycoderma aceti enters and at once begins to convert 

 the alcohol into acetic acid and we finally have vinegar. "Hard cider" 

 is simply apple wine in which the acetic acid fermentation has progressed 

 to an advanced stage. 



In the manufacture of the Japanese and Chinese rice wine (sake) 

 the maltose fermentation of the starch (in the rice grain) is brought about 

 by the Aspergillus oryzfe as already stated. The process of beer and 

 sake manufacture may be compared as follows: 



BEER 



SAKfi. 



i. Material Used 



Carefully selected barley is cleaned in 

 running water, then macerated in water 

 to induce germination. Rice, wheat and 

 other cereals may be added. Hops are 

 used. 



2. Diastase Fermentation. 



During the germinating process a fer- 

 ment or enzyme (diastase) is liberated 

 which converts the starch into saccharine 

 compounds. The ferment is unorganized 

 (non-living) and is soluble in water. The 

 germinating and fermenting grain consti- 

 tutes the beer wort. 



A good quality of rice is thoroughly 

 washed in cold water, then softened by a 

 steaming process. No hops used. 



Malting 



The steamed rice is spread on mats and 

 inoculated with tha spores and hyphse of 

 Aspergillus oryza. This fungus liberates 

 an enzyme (disastase) which converts the 

 starch into saccharine substances. The 

 enzyme produced by the fungus is soluble 

 in water. Fermentation takes place in a 



warm room. 



3. Alcoholic Fermentation 



The beer wort (Bierwiirze) is now ready 

 to be acted upon by the yeast organis us 

 (Saccharomyces cerevisece) which enter from 

 the air or which may be added in pure 

 culture. The yeast organisms convert the 

 saccharine substances into alcohol and 

 carbonic acid gas (02). 



The diastase and the yeast ferments are 

 both active during this process. 



The sake wort (moto) is prepared by mix- 

 ing the steamed rice and fungus (A. oryza) 

 in vats. Yeast cells (Saccharomyces of 

 sake) enter from the air and cause alcoholic 

 fermentation, converting the saccharine 

 substances into alcohol and carbonic acid 

 gas (COj). 



The diastase ferment (produced by A. 

 oryza) and the alcoholic ferment (Saccha- 

 romyces) are active during the entire 

 process. 



4. Expressing, Cooling, Clarifying and Pasteurizing 



These processes are very closely similar in beer and sake brewing. The differences, 

 if any, are slight and pertain to modifications of methods employed by different manu- 

 facturers. Preservatives, as salicylic acid, may be added. Both beverages may be rein- 

 forced with alcohol. This is not generally done with seke as the brewers declare thatjthe 

 addition of foreign alcohol destroys the characteristic flavor or bouquet. 



