New Process of Vinegar Making. 129 



the liquid, not leaving a vacant spot. During this time the 

 alcohol is acidified. While the operation is in full progress — 

 when, for example, half the original alcohol is transformed into 

 acetic acid — alcohol, or wine, or strong beer is added, day by 

 day, in small quantities, and the process continued until the 

 liquid is found to contain enough vinegar for commercial use. 

 While the plant is able to excite acetification we add alcohol ; 

 and when its action begins to be exhausted, we leave it to com- 

 plete the acetification of the alcohol still remaining in the liquid. 

 The plant is then separated from the fluid, and on washing, it 

 yields a slighly acid and azotized liquid, capable of ulterior use. 



" The fermenting tub is then put to fresh work. It is indis- 

 pensable not to suffer the plant to want alcohol, because in that 

 case its oxygen-transporting faculty would exert itself partly 

 on the vinegar, which it would transform into water and car- 

 bonic acid, and partly on those little understood volatile prin- 

 ciples, the loss of which renders the vinegar flat and destitute 

 of aroma. Moreover, if the plant is once turned away from 

 its vinegar-making action, it will only employ it again with 

 diminished energy. Another precaution, not less necessary, is 

 not to excite too great a development of the plant, for its activity 

 is then exalted without measure, and the acetic acid will be 

 partially changed into carbonic acid and water, even while 

 alcohol still remains in the liquid. A vessel of one square 

 metre (about thirty-nine inches) surface, holding fifty to a hun- 

 dred litres (say from ten to twenty gallons), will yield acetic acid 

 equal to five or six litres of vinegar a day." 



M. Pasteur recommends shallow wooden vessels, like the 

 coolers used in brewing, to be employed in this process. They 

 should be furnished with covers, with two small openings for the 

 entrance of air. Two tubes of gutta-percha fixed to the bottom 

 of the vessel, and pierced laterally with small holes, readily 

 permit the introduction of fresh supplies of alcohol without 

 disturbing the fungus film that forms on the surface. The 

 presence of phosphates is necessary, as they furnish the mineral 

 food of the plant, and if phosphate of ammonia be amono - 

 them, the plant takes from its base the nitrogen it requires, so 

 that complete acetification can be carried on in liquid contain- 

 ing a ten thousandth part of the phosphates of ammonia, potash, 

 or magnesia. 



Commenting on the advantages of this method, M. Pasteur 

 states that two processes of vinegar making are now employed 

 in France. One of these, called the Orleans process, is only 

 applicable to wine. It is carried on in casks ranged horizon- 

 tally, containing inferior vin ordinaire, and one-tenth of its 

 bulk of vinegar. After about two months each cask begins to 

 yield vinegar at the rate of about ten litres a week. In the 



