There are two ways to go about making red wine vinegar. The first requires purchasing a "vinegar mother" -- unpasteurized, living vinegar that reacts with wine and helps turn it, in turn, to vinegar -- or you can start from scratch and wait for the wine to turn naturally. Homemade red wine vinegar is preferable to store-bought versions, because the taste is less acidic, and brighter. Unless you are sure that the acidity of resulting vinegar is 4 percent or more, avoid canning or pickling with any homemade vinegar.
Making Your Own Mother
Making red wine vinegar involves a chemical process that converts carbohydrates like alcohol to acetic acid, the substance that gives vinegar its tangy taste. The vinegar mother used to aid in the conversion can be made by letting nature take its course. Simply take your favorite red wine and place it in a wide-mouthed jar until the jar is three-fourths full. Using some cheesecloth and a rubber band, cover the jar and place it in a warm, dark environment. Carefully shake the container every 2 weeks. Your vinegar mother, a gelatinous blob that floats near the top of the container, should form in a few weeks.
Vinegar Made From a Store-Bought Mother
If you choose to purchase your mother from a beer-and-wine-making supply store, you will save yourself some time. Using a wine that doesn't have a high alcohol content or one without added sulfites that inhibit the alcohol-to-acetic-acid conversion, will also help the process. Pour 1 bottle of wine into a wide-mouthed glass container that will hold at least 1 gallon of liquid. Add 2 cups of water, and the mother, to the container and cover it using some cheesecloth and a rubber band. Feed the concoction approximately once a week by adding additional leftover wine. Allow the mixture to mature for a few weeks or up to 2 months. When you have the desired taste of the vinegar, strain it into clean bottles.