TOP-FERMENTATION YEASTS. 33S 



When the principal fermentation was broken off, the liquid 

 contained 2-49 per cent, by vol. of alcohol ; during the two- 

 following periods (see above) 0-31 and 0-57 per cent, by vol. 

 were produced. 



Production of acid, after expulsion of CO 0! corresponds 

 to 5 c.c. of decinormal caustic soda solution. 



The fermented liquid has an agreeable smell and a fine- 

 aromatic taste. 



2. (Fig. 64, b, and Fig. 65, 6.) 



During fermentation most cells are free, medium-sized, 

 round and oval ; among them there occur round and oval 

 giant cells. 



The yeast lies loose in flask ; if shaken slightly, it is dis- 

 tributed like a cloud throughout the liquid. 



Film-formation : After 31 to 32 days, a few large patches. 



The cells of the film are smaller than those seen during- 

 primary fermentation ; ellipsoidal and slightly lengthened. 



The spores are big, if developed at a low temperature ; 

 formation of partition walls readily occurs. 



At 11 to 12 C. very few spores occur on the seventh day \ 

 at 25 C. rather abundant spore-formation in forty hours. 



When the principal fermentation was broken off, the liquid 

 contained 2-3 per cent, by vol. of alcohol ; in the two fol- 

 lowing periods 1 and 0-46 per cent, by vol. were formed. 



Acid-production : 6. 



Disagreeable smell and taste. 



3. (Fig. 64, c, and Fig. 65, c.) 



During fermentation the growth shows free cells and small 

 chain-formations of oval forms ; a few globular giant cells. 



The yeast lies very compact in flask ; it partially rises 

 in the liquid only when violently shaken. 



Film-formation : In 31 to 32 days the growth forms a very 

 thin film, which does not cover the entire surface of the liquid. 



Some of the cells of the film have the same size and shape 

 as those seen during primary fermentation ; others are slightly 

 lengthened. 



