WORK IN A VINEGAR FACTORY. 121 



greatest attainable strength (12 per cent, vinegar), but only 

 double vinegar with about 8 per cent, of acetic acid, two groups 

 might suffice ; the manufacture of a product of the greatest at- 

 tainable strength being, however, advisable in most cases, it is 

 recommended to arrange the factory for continuous work with 

 three groups of generators. 



For this purpose the number of generators must be divisible 

 by three; hence 3, 6, 9, 12, etc., generators have to be provided, 

 of which 1, 2, 3, 4, etc., form one group, so that, for instance, in 

 a factory working with 24 generators each group consists of 8. 

 By designating the generators belonging to one group with the 

 same number, we have groups I, II, and III, and in acidulating 

 and operating the generators belonging to one group are treated 

 in the same manner. 



For the preparation of the strongest vinegar (12 per cent.) the 

 generators belonging to group I can, for instance, be acidulated 

 with vinegar of 6 per cent, acetic acid, those of group II with 9 

 per cent, vinegar, and those of group III with 12 per cent, 

 vinegar. The process of operation is then as follows : 



Group I. The generators belonging to this group are charged 

 Avith an alcoholic liquid which yields vinegar with a con- 

 tent of 6 per cent, acetic acid, and the fluid running off is 

 poured back into the generators until a test shows the 

 alcohol, with the exception of a small remnant, to have 

 been converted into acetic acid. To this vinegar is then 

 added sufficient strong alcohol to form an alcoholic liquid 

 which will yield 9 per cent, vinegar. 



Group II. The alcoholic liquid for 9 per cent, vinegar is 

 poured into the generators belonging to group II, the 

 pourings being repeated until all but a very small quantity 

 of the alcohol is oxidized. The vinegar running off is 

 again compounded with sufficient alcohol to form alcoholic 

 liquid for 12 per cent, vinegar and is brought into 

 Group III. The pourings are here repeated until the oxidation 

 of the alcohol is nearly complete ; the finished product is 

 then subjected to storing or clarification. 



As will be seen from the above, in operating according to the 

 group system the entire factory is, so to say, divided into three 



