BEVERAGES 123 



tartaric acid and KHT. The specific gravity varies from 

 1015 to 1022. 



Cider Vinegar, from apple juice, is much used in America. 

 It contains 5 per cent of acetic acid, some malic acid, is 

 laevo-rotatory, and contains no aldehyde. 



White Vinegar is made by distilling malt vinegar. 



Wood Vinegar, by destructive distillation of wood. 



Vinegars from starch and glucose run the same danger 

 of arsenical contamination as beer made from these 

 substances. They are dextro-rotatory. 



Vinegar was formerly excisable, and to preserve it, 

 sulphuric acid was allowed .to be added, not exceeding 

 i/ioooth part by weight (duty abolished in 1844). 



Sodium carbonate or ammonia gives a purplish precipitate 

 in wine vinegar, but not in malt vinegar. 



ADULTERATIONS AND CONTAMINATIONS. Water, mineral 

 acids, pyro-ligneous acid, metals, colouring agents, preser- 

 vatives, gypsum, capsicum, vinegar eels. Vinegar is at 

 times pasteurized at 145 F. 



ANALYSIS. Specific gravity, total solids, ash, acetic 

 acid, free mineral acid, poisonous metals, nitrogen, and 

 phosphoric acid. Microscope for eels (Anguillula oxyphila). 



Specific Gravity. By sp.-gr. bottle or Westphal balance, 

 1015 to 1022. The sp. gr. of an artificial vinegar will vary 

 with the amount of acetic acid, caramel, and malt vinegar 

 it contains. Thus the acidum aceticum dilutum of the 

 B.P., which contains 4-27 per cent (by weight) of acetic 

 acid, and should yield no residue on evaporation, has a 

 sp. gr. of 1006. The sp. gr. of these vinegars will therefore 

 average above this figure. 



Total Solids. Evaporate 25 c.c. to constant weight in 

 a tared dish. Varies with the vinegar : malt, 2-50 per cent ; 

 cider, 2 per cent ; wine, i per cent ; white, 0-2 or less. 



Ash. Ignite at a low temperature. Should be alkaline 

 if free from mineral acid. Varies from 0-5 to O'2 per cent 

 in malt and cider, to 0-03 per cent or less in distilled. 



Alkalinity of Ash. Extract ash with hot water, titrate 

 with N/io acid, using methyl-orange as an indicator, 

 i c.c. N/io acid = 0-0047 g rm - K 2 O. About 0-026 per 

 cent in malt, and 0-14 per cent in cider vinegar. 



