As already stated, a very large proportion of vinegar is made in the United States from spirituous liquors. It is probable that fully 90 per cent. of the total production is obtained by the acetification of whisky. Much of this product is mixed with cider vinegar, or simply coloured with caramel, and then put on the market as apple vinegar. It is certain that the manufacturers of whisky vinegar, who are permitted by law to make “low wines” on their premises, without being subjected to the usual Internal Revenue Tax, are frequently enabled to perpetrate a fraud on the Government by disposing of the spirits so produced to the whisky trade, instead of converting it wholly into vinegar. To so great an extent is this practice carried on, that many of the cider vinegar producers have found it impossible to successfully compete with the less scrupulous manufacturers. Whisky vinegar is nearly colourless, usually possesses a greater strength than cider vinegar, and is free from malic acid. Cider vinegar exhibits a light-brownish colour and a characteristic odour. Some of the differences between these two varieties are shown by the following results, obtained by the author by the examination of samples of pure apple and whisky vinegar, fresh from the factories:-- -------------------------------+--------------+--------------- |Cider Vinegar.|Whisky Vinegar. -------------------------------+--------------+--------------- Specific gravity | 1·0168 | 1·0107 | | Specific gravity of distillate}| 0·9985 | 0·9973 from neutralised sample }| | Acetic acid | 4·66 p. c. | 7·36 p. c. Total solids | 2·70 „ | 0·15 „ Mineral ash | 0·20 „ | 0·038 „ Potassa in ash |Considerable | None Phosphoric acid in ash |Considerable | None | | Heated with Fehling’s solution}|Copious |} No reduction }| reduction |} | | Treated with basic lead }|Flocculent |} No precipitate acetate }| precipitate |} -------------------------------+--------------+---------------- Naturally the addition of caramel or cider vinegar to whisky vinegar would greatly affect the above tests. Attempts made to differentiate between the two samples by means of qualitative reactions for aldehyde and malic acid were not sufficiently distinctive in their results to be of much value. It has been suggested that the presence of _nitrates_ in vinegar would point to its origin from spirits. The apple vinegar manufacturer, however, frequently finds his product above the standard, in which case he reduces its strength by adding water, thus rendering this test of little or no avail.