WINE-MAKING IN CALIFORNIA. 293 



support the micoderms that necessarily perish when their 

 functions conversion of sugar into alcohol is accomplished. 

 Unless invigorated, fermentation proceeds very slowly to- 

 ward the end, as when the atmospheric oxygen is exhausted, 

 the alcohol formed seems to stupify the micoderms; a large 

 proportion of alcohol, or presence of alkaloids, (hops and 

 glycerine for instance) prevents or retards fermentation. 



Ground taste in wine is due to the gluten it contains and 

 improper treatment which brings out the taste. Air-treat- 

 ment removes with the gluten all tendency to ground taste. 



HOW AIR-TREATMENT IS APPLIED TO FLUID. 



To impregnate a fluid with a gas, we admit the gas below, 

 that it may rise upwards through the fluid. Accordingly the 

 air, to act most effectually, is admitted into the fluid in a 

 divided state by perforated pipes or mouth pieces, sunk near 

 the bottom of the vessel, impelled by an air-force pump. 

 Air-treatment of a hot fluid for purification from albumen re- 

 quires a vigorous and continuous current of air frequently for 

 hours to coagulate all albumenous parts ; for fermentation 

 however, periodical gentle currents are sufficient. 



TO WINE ESPECIALLY. 



A vigorous fermentation has been found the most satisfac- 

 tory for must as well as other mash, and a sufficiently high 

 temperature (75 to 85 F.) is essential. Fluctuation of 

 temperature should be avoided as always detrimental. When 

 the must is warmed (in a gathering tank) to about 65 to 70 

 F., the tanks or casks filled, the temperature steadily main- 

 tained, air is impelled vigorously for some ten minutes, and 

 unless sugar is added, a foaming up by a rising scum, will soon 

 take place. After this subsides (from six to ten hours) air is 

 gently impelled two or three times each day for about five 

 minutes at a time, till the fermentation is finished, which is 

 accomplished at the stated temperature in from five to" four- 



