RESEARCHES ON YEASTS. 



FIG. 18. 



character of the sedimentary yeast, and likewise in the taste 

 and odour of the finished beer, also in its stability and its 

 power of keeping its head. Whilst some yeasts give a beer 

 having a mild taste, and often with a milder flavour than that 

 of the corresponding beer which has been fermented with 

 impure yeast, 

 others, on the 

 other hand, 

 give a pro - 

 duct having a 

 stronger taste, 

 and some- 

 times a fruity, 



or a slightly bitter taste. By way of example, I will briefly 

 describe the Carlsberg yeast No. I and one of the yeasts 

 which in the Old Carlsberg brewery has been called No. 2. 



Fig. 1 8 represents cells of the Carlsberg yeast No. I as 

 they appear in the sediment of a wort culture which has stood 

 a few days at the ordinary room-temperature, or in the sedi- 

 mentary yeast taken from a fermenting vessel of the brewery 

 at the end of the primary fermentation. In addition to the 

 round and oval /->. 



cells, there are ^OxW 



many egg-shaped 

 and a few short 

 sausage - shaped 

 cells ; it is es- 

 pecially the egg- 

 shaped, somewhat 

 pointed form of 

 cell which, under the conditions mentioned, characterises this 

 species. Under conditions which, in the case of other species 

 hitherto examined, are favourable to spore-formation, this 

 species yields either very few spores or even none at all. 



Fig. 19 shows a growth of Carlsberg yeast No. 2. The 



