FABRICATION OF VINEGAR. 12o 



making the tests the product of all the generators of one group 

 is treated as a whole. A disturbance may, however, occur in 

 either one of the generators, and it would take considerable time 

 before its existence would be detected by a change in the consti- 

 tution of the entire product. The thermometer with which each 

 generator is provided is, however, a reliable guide as to the ac- 

 tivity of the latter, and if it shows in one of them a temperature 

 varying 37 to 39 F. from that prevailing in the others, it is a 

 sure sign of the respective generator not working in the same 

 manner as the others, and the product running off' from it should 

 be tested by itself as to its content of acetic acid and alcohol. 



Generally it will contain either no alcohol or very much of, it. 

 In the first case, the temperature of the respective generator is 

 higher than that prevailing in the others, and its activity has to be 

 moderated by decreasing the admission of air ; in the other case, 

 the generator works too sluggishly, and the difference is sought 

 to be equalized by increasing the current of air or giving a few 

 pourings of somewhat warmer alcoholic liquid. With a good 

 heating apparatus producing a uniform temperature in the work- 

 room such disturbances will, however, but seldom happen, and 

 by the use of the above means the normal working of the gene- 

 rators can be restored. 



CHAPTER XIII. 



DISTURBING INFLUENCES IN THE FABRICATION OF VINEGAR. 



IN no other industry based upon the process of fermentation 

 are irregularities and disturbances of such frequent occurrence as 

 in the fabrication of vinegar. Besides the nourishing substances 

 dissolved in the fluid and free oxygen, the vinegar ferment re- 

 quires a certain temperature for its abundant augmentation, by 

 which alone large quantities of alcohol can in a short time be 

 converted into acetic acid. By exercising the necessary care for 

 the fulfilment of these conditions serious disturbances can be 



