38 PURE CULTURES OF 



sunk to 30-35 C. ; if carried further, froth may readily be 

 carried over into the bent tube. My assistant Mr. Nielsen 

 found that 60 liters of air were used in the aeration of the 

 wort contained in one Carlsberg vessel, the time occupied 

 by this operation being 5-6 hours. Prior attaches a self- 

 acting aerating apparatus to the vessels.* 



Four or five of the previously mentioned glass flasks are 

 next inoculated with a vigorous growth of our pure culture ; 

 strictly speaking, we require only four, the fifth serving as 

 a reserve in case of accident. These are set aside at the 

 ordinary room-temperature, and in the course of a week 

 or less an abundant sediment of yeast will have formed. 

 The greater part of the beer is then decanted, only enough 

 being retained to detach the yeast. This is then introduced 

 into four of the Carlsberg vessels, each of the latter being 

 inoculated from one flask ; the yeast is introduced through 

 the tube a, Fig. 5. It is evident that all these operations 

 must be performed in such a manner that no infection can 

 occur from without For this some special knowledge and 

 no little practice are required, and these cannot be acquired 

 from a description. A distinct fermentation sets in by the 

 following day, and it is then, advisable to remove the filter 

 d. If it is desired to hasten the fermentation, the bent tube 

 should be heated and a portion of the carbonic acid gas 

 expelled by agitation. After about seven days as much 

 yeast will generally have formed as can be produced, and 

 the four vessels then contain sufficient yeast to pitch about 

 a hectoliter of wort. 



The above completes the work in the laboratory, the 

 further operations being conducted in the fermenting cellar. 

 For this purpose, a vessel of about \\ hectoliters capacity 

 is fitted up. This must be thoroughly cleaned, recently 

 varnished and covered over with a loose lid to allow the 

 escape of the carbonic acid gas. The wort must be aerated, 



* Bayer. Brauer- Journal, 1891. 



