HOW TO TEST VINEGAR.
Query.—G. G. writes: “Do you sell a thermometer or gauge for testing vinegar? How am I to know the degree of strength of the vinegar without a gauge?”
Ans.—Vinegar is tested with a special apparatus called a Twitchel Tester. Unless you use large quantities of vinegar, it would hardly pay you to go to the expense of buying such an apparatus as they are rather expensive and cost about $15 each. If you buy the vinegar by the barrel from the wholesale grocers and specify the degree of strength, they will give you the article desired. If you have any doubts as to the purity of vinegar there are various ways to test its purity. The adulterant of vinegar is sulphuric acid, which increases its indicated strength. Sulphuric acid can be detected by placing some of the vinegar to be tested in a saucer. Put some white sugar in the vinegar and evaporate to dryness by placing the saucer on top of a boiling water kettle. After the water has evaporated if the sugar turns black, the vinegar contains an adulterating acid. In lieu of a saucer, a teacup can be used in which the vinegar and sugar can be placed. The cup can then be placed in a basin of hot water in which it can be allowed to float until the vinegar in the cup is evaporated. If the vinegar contains free sulphuric acid the dry sugar will be found to be blackened. These are simple methods and are claimed to be more accurate as a test than the use of the Barium Chloride Test. The Barium Chloride Test is as follows: Mix one ounce of Chloride of Barium with ten ounces of water. A little of this mixture dropped in vinegar will quickly test its purity. If the vinegar contains sulphuric acid, this mixture will make it turn flaky at once, but if it remains clear and shows no change, the vinegar is free from sulphuric acid adulteration. Sulphuric acid makes vinegar show a very high test when, as a matter of fact, it is of very poor real vinegar strength.