366 STUDIES ON FERMENTATION. 



Let us call the ratio between the quantity of oxygen held in 

 solution by a wort, and that which the same wort would hold in 

 solution if saturated at the same temperature, the degree of 

 saturation of that wort at the temperature t. 



The determination of degrees of saturation is reduced to a 

 comparison of the number of divisions of hj^drosulphite w 

 which satisfies the wort in the first case, with the number n' 

 corresponding with the same wort saturated at the same tem- 



perature. The ratio -— gives the degree of saturation at the 



temperature t. 



In experiments made with a wort at 14'5° Balling as mean 

 density, we found the following results : — 



In summer, in the case of worts reduced to the temperature 

 of 5° C. (41° F.) by a refrigerator, the degrees of saturation 

 may be set down as — 



For unflltered worts . . . . 0*500 



For filtered worts . . . . . . 0"800 



In winter, in the case of some worts w^hich were racked at a 

 temperature of from 3° to 4° C. (37-4° to 39-2° F.), without the 

 use of a refrigerator, we found the saturation complete in both 

 worts. In the case of a very low external temperature, how- 

 ever ( — 10° C, 14^ F.), we have failed to determine the satura- 

 tion in an unfiltered wort. As regards the mean winter figures, 

 in the case of worts racked at a temperature of 5° C. (41° F.), 

 they may be fixed at these : — 



For unfiltered wort . . . . . . 0"850 



For filtered wort . . . . . . 950 



In autumn and spring we find the mean figures to be inter- 

 mediate between those given above : — 



For unflltered wort . . . . 0-500 to 0-850 



For filtered wort . . . . 0-800 to 0-950 



From these ratios it is easy to find the quantity of oxygen 

 contained in brewers' worts, if we also refer to Buusen's Tables 



