FABRICATION OF WINE-VINEGAR. 193 



racked when entirely bright into bottles remains, as a rule, un- 

 changed, it may happen to become turbid and form a sediment 

 which is shown by the microscope to consist of organisms. This 

 phenomenon is generally accompanied by a change in the odor of 

 the vinegar, and the acid taste loses sharpness and shows a pecu- 

 liar insipidity. From an accurate chemical examination the 

 cause of this alteration must be attributed to the decomposition 

 of the tartaric and malic acids in the fluid by a ferment. The 

 only sure remedy for this and all other alterations is to heat the 

 vinegar to 140 F. whereby all organisms are killed. For heat- 

 ing larger quantities it is recommended to pass the vinegar through 

 a coil of tin-pipe surrounded by boiling water and after rapidly 

 cooling the hot fluid to the ordinary temperature to store it for 

 some time in a barrel for the separation of the solid bodies. 

 Smaller quantities can be treated by bringing the vinegar into 

 glass bottles of 10 to 15 quarts 7 capacity, placing the bottles in a 

 boiler filled with water and heating to the required temperature. 

 A favorable result from heating can, however, only be obtained 

 with vinegar which has already acquired a fine taste and odor by 

 several months' storing. Freshly-prepared wine-vinegar still 

 showing the previously mentioned stupefying odor, if heated, 

 does not acquire the fine bouquet it otherwise would by storing. 



Preparation of Wine- Vinegar from Lees. 



The lees left from the pressing of the wine consist of the stems, 

 husks, and seeds of the grapes and contain a not unimportant 

 quantity of must which in many regions is sought to be obtained 

 by pouring water over them and subjecting them again to pres- 

 sure. The must thus obtained, though poorer in sugar and ex- 

 tractive substances than that of the first pressing, yields a drinkable 

 wine which is generally used for household purposes. All the 

 valuable constituents are, however, not extracted even by this 

 treatment, and the remainder can be profitably used for the pre- 

 paration of vinegar. In countries yielding wine of ordinary 

 quality it might even be advisable to entirely omit this treatment 

 of the lees with water in order to obtain an inferior quality of 

 .must, and use them directly for the preparation of vinegar. 

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