128 VINEGAR, CIDER, AND FRUIT-WINES. 



of vinegar. These phenomena are indicative of the generator 

 not being able to master the alcoholic liquid introduced and may 

 be due to the pourings being too large, or the temperature of the 

 alcoholic liquid poured in being too low, or finally to an insuffi- 

 cient draught of air. 



To restore the generator to a proper state of working, it is best 

 to try first the effect of smaller pourings and then an increased 

 draught of air. If the disturbance was due to an insufficient 

 draught of air, the temperature soon rises and the generator will 

 be able to work up the regular quantity of alcoholic liquid. By 

 the use of alcoholic liquid of a somewhat higher temperature the 

 restoration of the normal conditions can be accelerated. 



A decrease in the content of acetic acid in the fluid running 

 off from the generators without the presence of alcohol being 

 shown indicates a too vigorous process of oxidation, the alcohol 

 being not only oxidized to acetic acid, but the latter further into 

 carbonic acid and water. The temperature in the interior of the 

 generators rises considerably, about 45 F. above that of the 

 workroom. 



In this case the restoration of the respective generator to a 

 proper state of working is not difficult and can be effected in two 

 ways : either by considerably decreasing the ventilation of the 

 generator, or by pouring in a larger quantity of alcoholic liquid 

 than previously used. 



The heating of the generators is generally due to faulty con- 

 struction. Generators of large dimensions, as a rule, become too 

 warm much easier than smaller ones, the phenomenon also appear- 

 ing more frequently in summer than in winter; and "too warm" 

 being just as injurious to the efficacy of the generators as " too 

 cool," they must, during the warm season of the year, be as 

 carefully protected against too high a temperature as against 

 cooling during the cold season. This is effected, on the one hand, 

 by a suitable ventilation of the workroom during the night, and, 

 on the other, by the use of alcoholic liquid of a somewhat lower 

 temperature during the hottest season of the year. Moreover, 

 disturbances from too high a temperature of the exterior air need 

 only be feared in countries with a very warm climate. 



It has been frequently proposed to counteract a too vigorous 



