FABRICATION OF WINE- VINEGAR. 187 



With sufficient care the process of the formation of vinegar 

 could thus be uninterruptedly carried on for any length of time 

 by transferring the vinegar ferment from the finished vinegar to 

 the wine, if a cleansing of the vat were not from time to time re- 

 quired, on account of the accumulation on the bottom of the 

 vessel of decayed vinegar ferment and flakes of albumen which 

 have become insoluble. When the vat is to be cleansed the last 

 batch of vinegar is drawn off as long as it runs off clear, and the 

 turbid remainder in the bottom of the vat collected in a special 

 cask, where it is allowed to repose until clear. The vat is then 

 thoroughly cleansed with water, and after filling it again with 

 wine, the latter is mixed with pure vinegar ferment in the manner 

 already described. 



If, as may happen in very rare cases, mold ferment in the form 

 of the above-mentioned white spots appears upon the surface be- 

 sides vinegar ferment, the vat must be at once emptied. The 

 process should also be interrupted in case of the development of 

 the so-called mother of vinegar. The latter appears generally in 

 the form of a soft mass of the consistency of jelly submerged in 

 the fluid, and consists of vinegar ferment, which, however, does 

 not, on account of not being in direct contact with the air, pro- 

 duce acetic acid. The fluid to be acetified can be readily separated 

 from the mother of vinegar by filtering through a close cloth ; 

 the mother of vinegar remaining upon the latter and finally drying 

 to a whitish mass resembling very thin tissue paper. 



From the above it will be seen that the rational preparation of 

 wine-vinegar is a very simple matter ; but there are some diffi- 

 culties which can, however, be entirely prevented or readily re- 

 moved. The vinegar ferment is very sensitive towards sudden 

 changes in the composition of the fluid upon which it lives, as 

 well as towards quick changes in the temperature. The sudden 

 change in the composition of the fluid is prevented by not draw- 

 ing off all the finished vinegar, but allowing a small portion to 

 remain in the vat. The fresh supply of wine entering from be- 

 low then lifts up the remainder of vinegar, together with the fer- 

 ment floating upon it, and the mixture of both fluids is effected 

 so gradually that the change in the composition of the nourishing 



