Most commercial red wine vinegar is made using a speeded-up fermentation process (anywhere from 1 to 3 days); some of it is just lab-produced acetic acid, diluted with water and tinted red. Traditional red wine vinegar, left to ferment naturally on its own, takes several weeks and results in a much richer texture and flavor. The good news: It’s easy to make at home, and makes a great and unusual gift, too.
1 playing-card–size piece vinegar mother*
9 1/2 cups red wine, divided, plus more for maintenance feedings
1. Start the mother: Put the mother and 2 cups wine in a vinegar crock* and pour in 1 cup water. Cover the open top of the crock with a double layer of cheesecloth and secure with a rubber band around the rim. Put the container in a warm place (the ideal temperature for vinegar is 70° and 90°) out of direct sunlight; you can swaddle them in towels if you like, or put in a paper bag.
2. In 1 ½ weeks (maybe 2 weeks if it’s chilly weather), the bacterial conversion will have begun. Add 2 ½ cups red wine now, and twice more over the next 1 ½ weeks.
3. Vinegar is ready when it smells and tastes like vinegar: strong, sharp, and delicious. Homemade vinegar is exhilaratingly strong, so you may want to dilute it with a little water before using. If it smells like furniture polish, throw it away; it’s been contaminated and can’t be saved.
4. To continue growing your vinegar, just add 1 or 2 cups red wine every few weeks or so, tasting now and then to see whether it’s ready to bottle (if you want to bottle). Every several weeks, you’ll need to clean out the extra layers of mother that form and sink to the bottom (otherwise they’ll absorb all the vinegar). To do this, simply wash your hands well and plunge in. Leave the top layer behind.
5. To bottle the vinegar, strain it through a cheesecloth-lined plastic colander into clean bottles. Add water to dilute the sharpness if you like, and keep in the refrigerator. It is still “live”, but the cold will keep a new mother from forming in the bottle.
6. If you want to pasteurize the vinegar to store at room temperature, fill a 21-qt. boiling-water canner with hot water up to the first ring from the bottom, insert the canning rack upside down (handles down), and bring it to a boil, covered. Meanwhile, strain vinegar through a cheesecloth-lined colander into a large stainless-steel pot. Insert a clean deep-fry thermometer into vinegar and lower pot into boiling water. Turn off heat. Let vinegar heat to 155°; hold it there for 30 minutes, adjusting the heat as needed.
7. For room-temperature storage, pour the vinegar through a funnel into sterilized jars.
Vinegar mother. In the world of vinegar, a “mother” is a live starter, similar to a sourdough starter for bread. It is home to acetic acid-producing bacteria of the Acetobacter genus that convert wine to vinegar. The mother will form a not-unpleasant and actually quite fascinating thin, somewhat firm gelatinous layer on the surface of your vinegar crock. This is a sign that the bacteria are alive and well and doing their work. Find vinegar mothers from vinegar-making friends, at cheesemaking or beermaking supply shops, and online. To transport a fresh piece of mother given to you by a friend, put it in a little glass jar with a 50-50 mix of wine and water. Commercial products are sold in jars, ready to be used.
Vinegar crock. The best fermenting containers allow for a wide surface area and have an open top, so the bacteria have enough oxygen. They’re also enclosed, to keep out light (the bacteria are happiest in the dark). A 1-gallon iced-tea jar, shrouded in a towel, can work, but wide-mouthed canning jars are too narrow. The best containers are 5-liter Italian demijohns (find at oakbarrel.com) or 1-gallon clay crocks (find at claycoyote.com). The clay crocks have the added advantage of mellowing the new vinegar’s sharp acidity.