212 "DISEASES* OF BEER, 



^ part of the pitching yeast, the resulting beer proved, 

 after normal storage, to be appreciably less stable than the 

 corresponding beer which had been fermented with a pure 

 culture of the brewery yeast. 



As in the experiments described above with Sacch. ellip- 

 soideus II. and Sacch. Pastorianus III., the attenuation and 

 storage of the beer also plays an important part in this case. 

 The highly attenuated beer of the first series of experiments 

 was perfectly stable after two months' storage in the lager 

 cellar, in spite of the fact that one-fifth of the pitching yeast 

 consisted of Sacch. Pastorianus L When the beer attenuates 

 well during the primary fermentation, and is then stored for 

 not too short a period in a good cellar, it will not, as a rule, 

 be subject to yeast turbidity after it is subsequently drawn 

 off. When the diseased yeast is present in larger quantity, 

 however, it will be able to attack the beer in another way, and 

 there will be a deterioration as regards taste and odour. 



With regard to the effect produced by this species of 

 yeast, irregularities were also observed similar to those men- 

 tioned in the case of Sacch. Pastorianus III. and Sacch. 

 ellipsoideus II. 



In those cases where the infection occurred only after the 

 conclusion of the primary fermentation in the fermenting 

 cellar, that is to say, either during or after storage, no effect 

 was produced on the stability of the beer, except when a 

 comparatively large proportion of the disease yeast had been 

 present. 



Likewise, when a small quantity of the disease yeast is 

 present in the lager casks, in the pipes leading to these, or in 

 the bottles and small casks from which the beer passes to the 

 consumer, it will have no effect either in the one direction or 

 the other. This result is thus in agreement with the main 

 results of my experiments with Sacch. ellipsoideus II. and 

 Sacch. Pastoriamis III. 



The treatises which I published in 1883 and 1884 on the 



