ZYMOLOGY FERMENTS AND FERMENTATIONS 231 



going alcoholic fermentation is legion. Just how many different species, 

 varieties and forms of yeast organisms and associated organisms 

 are involved in the alcoholic fermentations (natural and artificial) n > one 

 knows. In commercial and manufacturing practice (iij wine, beer, 

 sake and brandy making, etc.) a distinction is made between upper 

 yeasts, lower yeasts, wild yeasts, etc. Each yeast species having its 

 varieties and forms characterized by special effects produced. 



The following are the principal yeast organisms known with the 

 principal fermentative activity of each. Hansen's distinction between 

 the genera Saccharomyces and Torula is based upon spore formation. 

 Saccharomyces form spores (ascospores, usually four in each ascus, 

 rarely eight), whereas Toruly does not. This is perhaps not a practicable 

 distinction. 



SACCHAROMYCES 



cereviseae, Hansen (a top yeast) 

 Pastorianus, Hansen (a bottom yeast) 

 intermedius, Hansen (top, feeble) 

 validus, Hansen (top yeast) 

 ellipsoideus, Hansen (a bottom yeast) 

 . turbidans, Hansen (bottom yeast) 

 willianus, Saccardo (found in floor), 

 boyanus, Saccardo (causes turbidity in beer) 

 logos, Van Laer (bottom and floor) 

 thermanitonum, Johnson (quick ferment) 

 ilicis, Gronlund (in Ilex) (bottom yeast) 

 aquifolii, Gronlund (in Ilex) 

 pyriformis, Ward (in Ginger beer) 

 vordermanni, W. & D. (in Arrak) 

 sake, Yabe (in sake) 

 batatse, Saito (in yam brandy) 

 cartilaginosus, Lindner (in Kephir) 

 multisporus, Hansen (a top yeast) 

 mali Kayser, Kayser (in cider) 

 marxianus, Hansen (on grapes) 

 exiguus, Hansen (in beerwort) 

 jorgensenii, Loschi, (causing turbidity) 

 zopfi, Artari (in syrup) 

 bailii, Lindner (in beerwort) 

 hyalosporus, Lindner (in wort) 

 rouxi, Butroux (in fruit juice) 

 soya, Saito (in Soya sauce) 

 unisporus, Hansen (in dutch cream) 

 flava lactis, Krueger (in cheesy butter) 

 hanseni, Zopf (in cotton and meal) 

 minor, Engel (in bread) 

 membranaefacions, Hansen 

 anomalous, Hansen (causing a fruity odor) 



