ALCOHOLIC FERMENTS. 149 



The discovery of isomaltose by C. J. Lintner, jun., has 

 opened up a new path in the study of the composition of 

 wort, whilst his investigations are of great importance, in 

 that they also give us a more intimate knowledge of the 

 process of fermentation. 



Very recently the budding-fungi have been also eagerly 

 looked for in milk. Grotenfelt discovered a Saccharomyces 

 (page 180), whilst various budding-fungi (pages 192-194) not 

 belonging to this genus were found by Duclaux, Adametz, 

 Kayser, and Beyerinck; they all hydrolyse milk-sugar. 

 These species have not yet been found in breweries. 



Fermi found that certain white and red species of yeast 

 are capable of exercising a diastatic action. Morris, in 

 experiments with pressed yeast, arrived at similar results. 



The different action of the Saccharomyces species on the 

 same nutritive liquid (e.g., wort, must) and under the same 

 conditions, has been further studied by Borgmann, Amthor 

 and Marx. 



According to Borgmann's experiments, the chemical 

 changes brought about in wort by the two Carlsberg 

 bottom-yeasts, No. 1 and No. 2, show a pronounced differ- 

 ence. These two species which had been in use for some 

 time in the fermenting-room, and were still practically pure 

 were employed for pitching two fermenting vessels con- 

 taining wort from the same brew ; the fermentation took 

 place under conditions which enabled a true comparison to 

 be made, and the resulting beer was stored as usual. The 

 differences in the chemical products were especially pro- 

 nounced in the proportion of free acid (No. 1 contained 

 in 100 c.c., 0-086, and No. 2, 0-144 acid, calculated as 

 lactic acid), and glycerine (No. 1 contained 0-109 and 

 No. 2, 0-137). 



As a result of these experiments, Borgmcmn points out 

 that the ratio between the alcohol and glycerine in these 

 two beers differs from that previously found in beers, the 

 ratio obtained from previous analyses being : 



