16 PURE CULTURES OF 



able to effect the whole fermentation in a desirable manner, 

 both primary and after-fermentation, has been proved by the 

 production of large and small quantities of beer by means of 

 absolutely pure cultures in sterilised wort. Amongst the 

 other species was the one with which I conducted my experi- 

 ments in 1882, and of which I gave a detailed description in 

 one of my papers published in 1883 ; it is there described 

 under the provisional name Sacch. Pastorianus L It was 

 this species alone which produced the disease. Further, it 

 was found that the beer was excellent which had been 

 produced with the help of the selected brewery yeast alone, 

 whilst an addition of Sacch. Pastorianus I. gave rise to the 

 dreaded bitter taste and disagreeable odour. This result was 

 of great importance, for Jacobsen had now to acknowledge 

 that a reform was really at hand, and he admitted its 

 introduction throughout his extensive brewery. At first he 

 proceeded even more rapidly than I myself desired. The 

 struggle for this matter in Old Carlsberg was thus ended. 

 This occurred in 1884. I have here laid stress upon the 

 observations in the two breweries named, partly because they 

 show how the matter developed, and partly because they 

 speak in a striking manner for the reform which I wish to 

 become disseminated as widely as possible. 



The experiments made both in the brewery and in the 

 laboratory, showed that Jacobsen's fears with reference to the 

 after-fermentation were groundless. In recent years, indeed, 

 it is only with regard to high fermentation in English 

 breweries, that the objection has been raised that a pure 

 culture of a single species is unable to effect the desired 

 after-fermentation. Experiments which were conducted in 

 the brewery have shown, however, that also in this case the 

 objection is without foundation. This question will be 

 discussed more in detail in a subsequent chapter which 

 deals with the employment of pure yeast culture in high 

 fermentation breweries. Influenced by these objections, 



