TREATMENT OF FRESHLY-PREPARED VINEGAR. 153 



The sulphurous acid dissolved in the vinegar is after some time 

 converted into sulphuric acid and its presence can be readily de- 

 tected. It may, however, be remarked that the quantity of sul- 

 phuric acid reaching the vinegar in the above manner is an exceed- 

 ingly small one, and, moreover, is partially fixed to the mineral 

 bases (lime and magnesia) contained in the water used in the 

 preparation of the alcoholic liquid. Hence a manufacturer who 

 sulphurs his barrels need not fear being accused of having adul- 

 terated his vinegar by the direct addition of sulphuric acid. 

 Sulphured vinegar must be stored at least several weeks before it 

 is salable, the odor of sulphurous acid adhering to it perceptibly, 

 and disappearing only at the rate at which the sulphurous acid is 

 converted into sulphuric acid. 



Fining of Vinegar. 



In a manner similar to that of wine, vinegar can be obtained 

 bright by " fining" with isinglass. This method offers no advan- 

 tages as compared with filtration, though it is employed by many 

 manufacturers. The isinglass to be used is prepared as follows : 

 One to two grammes (0.56 to 1.12 drachms) of isinglass per 

 hectoliter (22 imp. gallons) are cut into narrow strips with the 

 scissors and soaked in water in a porcelain dish for twenty- 

 four hours. The jelly-like, nearly colorless mass is pressed 

 through a linen cloth. A solution of 0.6 to 1.2 gramme (0.033 

 to 0.067 drachm) of tannin per hectoliter (22 imp. gallons) is 

 then added to the isinglass and the mass diluted with vinegar. 

 The whole is then thrown into the barrel and thoroughly mixed 

 with the contents. The clarified vinegar is finally drawn off 

 from the sediment. 



Coloring Vinegar. 



Vinegar prepared from alcohol is either clear as water or only 

 slightly colored. Before the general introduction of the quick 

 process consumers were accustomed to the dark yellow product 

 prepared from wine or beer, and many are still prejudiced against 

 slightly-colored vinegar, considering it weaker. Unfounded as 



