22 PURE CULTURES OF 



A pure cultivated yeast separated from an ordinary im- 

 pure brewery yeast, and which will therefore, as a rule, have 

 sprung from a mixture of several different species, will not 

 give exactly the same product as the mixture. In the taste 

 especially there is almost always a small and sometimes even 

 a very noticeable difference. It is consequently a mistake 

 made by several brewers who have imagined that pure 

 cultivated yeast would give them a beer having exactly the 

 same taste as the beer obtained with the impure yeast from 

 which the pure culture was originally separated. They obtain 

 a finer and above all a constant product, but one differing 

 somewhat from their former beer. This fact cannot be too 

 strongly emphasised. A brewer, therefore, commits a great 

 practical error when he suddenly introduces pure yeast 

 throughout the whole brewery. In such a case it may readily 

 happen that the beer will suddenly assume a different 

 character, which may be displeasing to many customers. 

 The change must be introduced by degrees, and then nothing 

 different occurs from that which has formerly always occurred 

 in every brewery. When it is thoroughly introduced a great 

 advantage has been gained. Captain Jacobsen, the late 

 owner of Old Carlsberg, on several occasions clearly and 

 forcibly emphasised the conditions affecting this matter ; 

 nevertheless misunderstandings and mistakes still occur 

 every day. 



The question might perhaps be asked whether it would 

 not be possible to impart a particular flavour to the beer 

 by the employment of mixtures of yeast of known composi- 

 tion, and thus produce differences in the taste which might 

 find favour with the public. That this could now be rationally 

 carried out is self-evident. The culture yeast could for 

 instance be mixed with a wild yeast which, like my Sacch. 

 Pastorianus //., produces no sickness. In some cases the 

 admixture could be made with the pitching yeast, and in 

 others it could be introduced at the end of the primary fer- 



