STUDIES ON FERMENTATION, 383 



Temperature Temperature 



of Wort. of Eoom. 



Feb. 5, 9 a.m. . . 21° C. (69-8° F.) 8° C. (46-4° F.) 



12 a.m. . . 19-75° C. (66-6° F.) 8° C. (46-4° F.) 



4 p.m... 18° C. (64-4° F.) 8-5° C. (47-3° F.) 



Feb. 6, 11 a.m. . . 14° C. (57-2° F.) 8° C. (46-4° F.) 



Feb. 7, 2 p.m. . . 11° C. (51-8° F.) 7° C. (44-6° F.) 



At the end of this time the wort drawn from the smaller 

 tap half-way up the vessel had already become very bright^ 

 although it was taken from the bulk of the liquid above the 

 deposit of hops. 



On February 8th the temperature of the wort was 9 '5° C, 

 (49-1° F.), and that of the room 5° C. (41° F.) ; the wort was 

 again very bright. Taken from the small tap and tested b}^ 

 Schlitzenberger's process it gave no evidence of free oxygen 

 in solution, although its surface was in contact with air. It 

 continued absolutely pure, the arrangements of our vessel, as 

 we have already explained, allowing only such air to enter as 

 was first dejDrived of its disturbing germs. 



Not till February 12th, after we had again determined the 

 purity and brilliant clearness of the wort, a brilliancy which we 

 can compare with nothing so well as Cognac, without the 

 faintest trace of cloudiness, did we set it to ferment in a vessel 

 similar to that in which it had cooled, but without the false 

 bottom. In the process of transfer we effected its aeration by 

 causing it to fall on a small inverted tinned iron capsule some 

 4 or 6 centimetres (IJ to 2 inches) in diameter. By this 

 arrangement the wort took up air to the extent of rather more 

 than a third of its saturate capacity, that is to say, by spreading 

 over the capsule, and falling from it in a kind of sheet, it 

 absorbed a volume of oxygen more than a third of the total 

 amount of oxygen which it was capable of absorbing at the 

 existing temperature ; this was 12° C. (53'6° F.) at the moment 

 when the wort was drawn off. The pitching was accomplished 



