Do you see it? That slimy red substance at the top of this ceramic jar is called a mother of vinegar, or vinegar mother. It's basically a combination of cellulose and acetic acid bacteria that forms on fermenting alcoholic liquids. As the name implies, a mother of vinegar makes vinegar!
What You Need
2 bottles of wine
Mother of vinegar
Equipment [OR] Tools
Wide ceramic mouth crock with spigot
When added to wine, cider, or other alcoholic liquids, a vinegar mother creates vinegar with a little help from oxygen. Mother of vinegar sometimes forms in store-bought vinegar bottles when some sugar or alcohol somehow gets into the vinegar when it was bottled. It shows up as a thin layer of slime floating on top of the vinegar. It's harmless and can be filtered out using cheesecloth or a coffee filter. Bragg's Apple Cider Vinegar comes with the mother.
To make your own vinegar, purchase a wide mouth crock with a spigot at the base. Don't use glass or plastic because the vinegar and its mother need to be in a dark place. Next, you need the mother and two bottles of wine. If you've got a mother formed in a bottle of vinegar, great! If you don't already have a mother, you need the acetic acid bacteria - it's called mycoderma aceti and often comes in a jar and looks like clear liquid. It can be purchased in winemaking supply stores, which are easily found via your favorite online search engine.
Either way, take your vinegar mother or mycoderma aceti, dump it in the crock, empty the two bottles of wine, and let this mixture work its magic. Don't seal the crock completely - the mother of vinegar requires oxygen. Cover it with a few layers of cheesecloth secured with a rubber band - this way it can still breathe, and this will keep dust and bugs out of the vinegar. Place the crock in a medium-warm (60°-85°F), dark place.
At first, the bacteria will look like a transparent haze in the wine. Left undisturbed and given oxygen, it grows into a solid blob that covers the top of the liquid. Once the mother is established, feed it once a week with a glass of wine. Don't add fortified wines such as port or sherry.
In a few months, you should have vinegar. White wine takes longer to ferment than red wine does - reds usually take three months while whites can take up to 6 months. This is due to the difference in sulfide content in the wines. Since the mother floats at the top, use the spigot at the bottom to access your vinegar. Filter it a few times through coffee filters to remove sediment. When the vinegar mother eventually sinks to the bottom of the crock, throw it out or give a slab to a friend so they can make their own vinegar.
More tips on vinegar making, along with troubleshooting tips, can be found here.
Good Question: What Is This Slime In My Vinegar?
Vinegar: Does It Have a Shelf Life?
Recipe: Sauerbraten - a delicious roast beef marinated and braised in vinegar
What's the Deal With: White Balsamic Vinegar?
Pickling: Choosing a Vinegar
Drinking Vinegar: Have You Ever Made a Shrub?
Post originally published September 28, 2009
(Image: Kathryn Hill)