46 VIXEGAR, CIDER, AND FRUIT- WIXES. 



cally calculated quantity of air must pass through the apparatus 

 to completely convert the alcohol into acetic acid. Hence 100 

 grammes of alcohol require at least 942.92 liters of air for their 

 conversion into acetic acid, and, without being far wrong, it may 

 be assumed that in a vinegar factory, in round numbers, 1000 

 liters or one cubic metre of air are required for every 100 grammes 

 of alcohol to be converted into acetic acid. 



A vinegar generator can, on an average, convert daily 3 liters 

 of alcohol into acetic acid ; 3 liters of absolute alcohol (specific 

 gravity 0.794) weigh 2382 grammes. Now, if, as stated above, 

 1 cubic metre of air is required for every 100 grammes of alcohol, 

 it follows that 23.82 cubic metres, or 23,820 liters of air must 

 pass daily through each vinegar generator in operation.* 



Calculated to 16 working hours a day, somewhat more than 0.4 

 liters (more accurately 0.413 liters) must pass every second through 

 the generator in order to supply the quantity of oxygen required 

 for the conversion of alcohol into acetic acid. 



Since the formation of vinegar has theoretically to be con- 

 sidered as a process of combustion, in which of 46 parts by 

 weight of alcohol 2 parts by weight of hydrogen, or of 100 parts 

 by weight of alcohol 4.34782 parts by weight of hydrogen, are 

 consumed, the quantity of heat liberated by the conversion of 

 100 parts by weight of alcohol into acetic acid can also be calcu- 

 lated. By combustion 1 gramme of hydrogen yields 34.126 

 units of heat, and hence 4.34782 grammes of hydrogen 148.373 

 units of heat, i. e., in the conversion of 100 grammes of alcohol 

 into acetic acid sufficient heat is liberated to heat 148.373 kilo- 

 grammes of water from C. to 1 0., or 1.48 kilogrammes from 

 C. to boiling, and thus a considerable development of heat is 

 caused by the rise of temperature in the apparatus in which a 

 vigorous formation of vinegar takes place. 



In answer to the question, what can the practical manufacturer 

 of vinegar learn from these theoretical explanations, it may be 

 said there are many points of great importance for the execution 

 of the work. The calculation of air shows that the alcohol 



* It is always supposed that the manufacture of vinegar is effected in 

 generators used in the quick process. 



