THE MANUFACTURE OF VINEGAR , 545 



tions. It is the oldest commercial method and produces vinegar of the 

 highest quaUty. 



Barrels of about two hectoliters are usually employed, fitted 

 essentially like that already described but with the omisson of the 

 funnel and drawing-o£E tubes. 



The wine is first cleared in a vinegar filter. This consists of a 

 wooden vat filled with beech chips which have been extracted by soak- 

 ing for several days in cold water. The wine remaining in contact 

 with these chips for three or four days deposits most of its sediment. 



The cask is first one-third filled with good vinegar and 10 or 15 

 1. of the filtered wine added. The sarhe amount of wine is added every 

 week for four weeks by which time the cask is half full. At the end of 

 the fifth week an amount of vinegar equal to the wine added is drawn 

 off and the operation repeated. The vinegar is filtered as soon as it is 

 drawn off, placed in full tightly bunged casks and kept in a cool 

 cellar. 



Pasteur Method. — ^Pasteur long ago pointed out the defects of the 

 old Orleans method and suggested improvements. The main defects 

 of the old method are that it is cumbersome, laborious, slow and costly. 

 There is a loss of about 10 per cent of material by evaporation and the 

 repeated additions of liquid break the bacterial film, which then sinks 

 to the bottom, grows anaerobically and exhausts the nutrients of the 

 solution without producing acetic acid. These submerged bacteria 

 finally form a large gelatinous mass which interferes with the regular 

 progress of the operations, depreciates the quaUty and necessitates 

 frequent expensive cleanings of the casks. Many attempts, more or less 

 successful, to overcome these defects in accordance with Pasteur's ideas 

 have been made, that of Claudon is one of the best and will serve to 

 exemplify all. 



It consists essentially of a wide, shallow, covered square vat, 

 furnished with numerous openings near the top hy which the entrance 

 of air can be facilitated and regulated. This vat is filled to the bottom 

 of the air vents with a mixture of four parts of good new vinegar and 

 six parts of wine which has been pasteurized at 55° and, when necessaty, 

 filtered. On top of this liquid is floated a light wooden grating which 

 helps to support the bacterial film and prevent its breaking and sub- 

 merging dtiring the various operations. When filled, the process is 

 started by placing a small quantity of a good bacterial film on top of 

 35.. 



