1749. To Strengthen Weak Vinegar

1749.    To Strengthen Weak Vinegar. If in pickles, turn it off, heat it scalding hot, put it in the pickles, and when lukewarm, put in a small piece of alum the size of a filbert, and a brown paper 4 inches square, wet with molasses. If it does not grow sharp in 2 weeks it is past recovery, and must be thrown away. Or, freeze it and remove the ice which forms on the surface. The water of the vinegar alone freezes, leaving the acetic acid in solution in the remaining water.

1750. To Determine the Strength of Vinegar

1750.    To Determine the Strength of Vinegar. The hydrometer is not to be much relied on in testing the strength of vinegar. The simplest test is to take a fragment of fine marble, weigh it and suspend it by a thread in a known measure of vinegar until all action ceases and the liquid has no longer a sour taste. Take out the marble, wash and dry it, and note the loss of weight it has sustained. 5/6 of this is real (hydrated) acetic acid. An ounce of good vinegar should saturate from 30 to 32 grains of pure and dry carbonate of soda; such vinegar contains about 5 per cent, of anhydrous (absolute) acetic acid. Vinegar above 30 per cent, of real acid will dissolve the essential oils and camphor. The strength of vinegar may also be ascertained in the same way as any other acid (see Nos. 69 and 78); but vinegar manufacturers designate the strength of their products by the number of grains of pure carbonate of potassa required to neutralize 1 fluid ounce of the vinegar tested. Thus, if 1 fluid ounce of a sample of vinegar requires 16 grains of carbonate of potassa to neutralize it, the vinegar is said to be of a strength of 16 grains.

1751. To Deprive Vinegar and Other Vegetable Liquids of their Color

1751.    To Deprive Vinegar and Other Vegetable Liquids of their Color. To take away the color of vinegar, 2 pints red wine vinegar, cold, are mixed with l1/2 ounces bone-charcoal (prepared as directed in the next receipt) in a glass vessel. Shake this mixture from time to time, and in 2 or 3 days the color completely disappears. "When the process is to be performed in the large way, throw the charcoal into a cask of vinegar, which must be stirred from time to time. The highest colored red wines treated in the same manner become perfectly limpid. Ivory-black possesses the same property as bone-black. Filtering through charcoal will produce the same result.

1752. To Prepare Animal Charcoal to Decolorize Vinegar and other Vegetable Liquids

1752.    To Prepare Animal Charcoal to Decolorize Vinegar and other Vegetable Liquids. Fill a crucible with the most compact parts of ox and sheep bones, lute the cover, carefully leaving only a small opening at the top, place the crucible on a forge fire, and heat it gradually till red; when the flame from the oily and gelatinous parts has ceased, diminish the opening and suddenly raise the fire; when cold, reduce the charcoal to fine powder. (See No. 1729 (Properties of Charcoal).)