Prepare red wine vinegar by placing a piece of mother of vinegar into a 1-gallon crock and adding a bottle of good quality wine with 2 cups of water. Then, place the crock in a cool dark location, and feed the crock weekly with about a cup of leftover wine.
Preparing vinegar from wine takes about three months. While the wine is going through the second fermentation process to form vinegar, secure cheesecloth over the top to allow air enter the container.
The mother is a layer that forms on top of wine as it goes through the process of forming vinegar. It contains the microorganisms that are responsible for the process. Get a piece from a friend who makes vinegar or purchase it at a wine and beer making store. Each time you decant the vinegar from the crock, add more wine so that the mother remains active, which it can do for years.
When the vinegar is ready for use, remove it from the crock before diluting it with water to the acidity level you desire. Adding 1 part water to 3 parts vinegar is a good starting point. Keep the vinegar clear, and prevent it from forming a new mother by placing it and the water in a pot before heating it to 155 degrees Fahrenheit and maintaining that temperature for 30 minutes. Store the pasteurized vinegar in clean glass or other nonreactive bottles.