224 "DISEASES" OF BEER, 



under certain circumstances, a good brewery yeast can play 

 the part of a disease yeast, the next problem was to deter- 

 mine whether this was also the case under the conditions 

 obtaining in the brewery. With this object I undertook 

 the two following series of experiments, in which the method 

 adopted corresponded with that of the experiments de- 

 scribed above. The plan of the experiments has, in fact, 

 been practically the same throughout, and is described in 

 greatest detail in that part of the chapter which deals with 

 Sacch. ellipsoideus II. and Sacch. Pastorianus III. 



II. Series of Experiments Two of the wooden vessels, B and D, 

 which have been already mentioned, were charged each with i hecto- 

 liters of lager-beer wort (14*4 per cent. Ball.) in the fermenting cellar of 

 the Old Carlsberg brewery. The temperature of the wort when the yeast 

 was added was 7 C. 



B was pitched with 400 grams of Carlsberg bottom yeast No. 2. 



D 360 No. 2, 



and 40 grams of Carlsberg bottom yeast No. i. 



The yeast was of fairly thick consistency, and consisted of young 

 vigorous growths which had been grown in wort at about 10 C. After 

 nine days the extract was 7*96 per cent. Ball, in B, and 8*04 per cent, 

 in D. B was bright, and D fairly bright. The beer from each vessel 

 was run into two casks, and these were then placed in the lager cellar, 

 the temperature of which was about 2 C. 



When the beer had been stored for one-and-a-quarter months, a large 

 number of bottles were filled from one cask of each beer, and these were 

 put away in a dark cupboard at the ordinary room-temperature. The 

 extract of B was 7 '23 per cent. Ball., and that of D 6-90 per cent. Both 

 beers were perfectly bright. After eleven days there was still no sediment. 

 After fifteen days B was still free from yeast turbidity, whilst D showed 

 commencing turbidity. After three months' storage samples were taken 

 in the same manner from the second series of casks. The extract of B 

 was 6*49 per cent. Ball., and of D 6*41 per cent. The beer was perfectly 

 bright. After standing ten days there was still no sediment. Five days 

 later there was a very slight sediment in B, insufficient to cause yeast 

 turbidity when shaken up ; in D there was slightly more sediment, and 

 on agitation the beer became a little cloudy. The difference noticeable 

 after one-and-a-quarter months' 1 storage had thus almost completely 

 disappeared when the storage period was prolonged to three months. 



III. Series of Experiments. The wort employed in this series of 

 experiments had an extract of 14 per cent. Ball. ; the fermentation was 

 carried out in four vessels. 



