Vinegar, Homemade from Wine or Cider

The end of the road for every fermented drink here, and the one ferment with a hard dependency: acetic bacteria eat ALCOHOL, so something has to make the alcohol first. You cannot go from sugar to vinegar directly. The other thing to know is that it is aerobic — the opposite of every vegetable ferment in this section, which is why it lives in a wide open vessel instead of under brine.

Ingredients

• 1 quart leftover wine, hard cider, beer or over-fermented kombucha, diluted to 5–9% ABV
• 1 cup raw unpasteurized vinegar, or a mother of vinegar
• Water for diluting
• A wide crock, jar or bowl, and a cloth

Directions

1. Key ingredients
2. Something alcoholic at 5–9% ABV, and live raw vinegar as the starter.
3. Dilute if needed. Most table wine is 12–14% ABV, which INHIBITS the bacteria — cut it roughly 2 parts wine to 1 part water to land near 7–8%. Too weak and you get weak vinegar; the acidity ceiling is set by the starting alcohol and cannot be raised later.
4. Add raw live vinegar, about 20% by volume. Pasteurized supermarket vinegar will NOT work — nothing in it is alive.
5. Use a WIDE vessel. Surface area is the rate limiter because the bacteria need oxygen at the interface. A narrow bottle takes forever.
6. Cover with cloth, not a lid. It must breathe.
7. Somewhere warm and dark, 77–86 °F — warmer than most ferments here. Cool rooms work slowly.
8. Wait 3 weeks to 6 months. Do not stir; you will sink the mother. Taste from a month on.
9. Bottle when sharp enough, leaving the mother behind to start the next batch. Optionally age it — vinegar mellows and rounds considerably over months.

Notes

PROVENANCE. Mine, and mostly a way of not pouring away the end of a bottle.

THE MOTHER IS NOT THE CULTURE. It is bacterial cellulose — a biofilm the acetic-acid bacteria build, the SAME material and the same genus (Komagataeibacter) as a kombucha pellicle. You inoculate with live liquid; a mother comes along and one will form regardless.

FRUIT-SCRAP VINEGAR is the beginner version and needs no starting alcohol: apple cores and peels covered in sugar water, fermented open for a couple of weeks so wild yeast makes the alcohol, then strained and left to acetify.

DO NOT USE HOMEMADE VINEGAR FOR CANNING. Tested pickling recipes assume 5% acetic acid, and you do not know the strength of yours. Weaker vinegar can leave a canned product above the pH 4.6 line where C. botulinum can grow. Homemade vinegar is for eating, dressing and marinating; buy commercial 5% for anything you intend to can. Note also that rice vinegar is often only about 4%, so it is not a drop-in substitute in a canning recipe either.

VINEGAR EELS — tiny harmless nematodes — can appear in raw vinegar. Unsettling, not dangerous; filter and heat to 150 °F if you would rather not.

FRUIT FLIES are the real pest of any open aerobic ferment. Tight-woven cloth.