390 STUDIES ON FERMENTATION. 



It is seldom that an industry adopts at once in their entirety 

 new practices which would necessitate a re-arrangement of 

 plant, and the process of which we are speaking would require 

 such re-arrangement, as far as the fermenting vessels and the 

 method of cooling the wort are concerned. The new process 

 would, however, be of great value if once introduced, simply 

 for the manufacture of pure ferment and pure wort, or even for 

 that of pure ferment alone. In other words, we might retain 

 the ordinary methods employed in low fermentation, use the 

 same method of cooling or the new one, the same fermenting 

 vessels, and the process of fermentation at low temperatures ; 

 the yeast, however, would be prepared in a state of purity in 

 the closed vessel which we have described, collected in those 

 vessels, aerated, and then employed after the old-established 

 custom ; better still, the pitching might be performed with beer 

 in the act of undergoing pure fermentation. 



Above the fermenting-stage there might be arranged a room 

 for the vessels used in the new process, from which the pure 

 beer could be run for pitching purposes into the large tuns in 

 the brewery below. It is true that beer prepared in this manner 

 would not be perfectly pure, but from the results which have 



increase this at will, by causing the wort as it comes from the copper and 

 the hop-back to pass into a cylinder turning horizontally on its axis and 

 furnished with blades fixed inside, so as to divide the wort and bring it 

 better into contact with the air in the cylinder. Instead of a revolving 

 cylinder we might use a fixed vessel, in which the wort could be stirred 

 up by some arrangement outside. In either case we should have to 

 take care that the air was pure when it came into contact with the wort, 

 but this would be a matter of no difficulty ; we would simply have to 

 make communication with the outer air by means of a tube filled with 

 cotton wool. Any air that might bo in the vessel at the moment when 

 the wort was introduced would be purified by the high temperature of 

 the wort coming from the copper. We should, moreover, gain the great 

 advantage of being able to bring oxygen to bear on our wort in deter- 

 minate amounts. From this vessel it would pass on to the refrigerator. 

 We might again raise the wort oxidized on the coolers to a temperature 

 of 75" C. (107^ F.), to recool it in this manner and aerate it by means of 

 the pure- air pipe. 



