Vinegar · Guide

Vinegar Mother: What It Is, How to Grow One and How to Keep It

The mother of vinegar is a mat of cellulose made by acetic acid bacteria. What it looks like, how to grow one from raw vinegar, how to tell it from mould, why it sinks, and how to store a mother between batches.

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Translucent vinegar mother lifted above an amber vinegar culture

Updated October 2026 · 7 min read

The mother of vinegar is the slippery, pancake-like mass that floats on top of a vinegar crock or drifts at the bottom of a bottle of raw cider vinegar. It looks alarming the first time you see it, but it is simply the home of the bacteria that make vinegar, and it is the easiest way to start your next batch.

What a vinegar mother is

Acetic acid bacteria need oxygen to turn alcohol into acetic acid. To stay at the surface, where the air is, they produce strands of cellulose that knit together into a floating mat. That mat, with the bacteria living in and on it, is the mother.

What it looks like A smooth, wet, gelatinous layer, from a cloudy skin a millimetre thick to a rubbery disc a centimetre or more. Pale beige on cider or white wine, pink to brown on red wine.
What it is not It is not a fungus, and it is not mould. A mother never has fuzz, and it is wet rather than dry or powdery.

The same kind of mat forms on kombucha, where it is called a SCOBY. The two are cousins rather than twins; the kombucha mother guide explains how the kombucha version differs.

How to grow a vinegar mother

  1. 1
    Mix the base In a wide glass jar, combine 1 part raw, unpasteurized vinegar (the cloudy kind with sediment) with 3 parts wine or hard cider. Low-sulfite wine works best.
  2. 2
    Cover and leave Cover with tightly woven cloth and a rubber band. Keep it somewhere dark at 20–30°C and do not move it.
  3. 3
    Watch the surface A faint, cloudy skin appears in 1–3 weeks and thickens over the following weeks. That skin is your new mother.
  4. 4
    Use it Lift it out with clean hands or a wooden spoon and add it, with a cup of its vinegar, to a new batch.

Mother or mould?

Mother smooth, glossy and wet; lies flat on the surface or hangs in the liquid; may have bubbles trapped under it; smells sharply of vinegar.
Kahm yeast a flat, wrinkled, dull white film, sometimes powdery. Common when the liquid is not acidic enough yet. Skim it and add more raw vinegar.
Mould dry, fuzzy, raised spots or patches, often green, blue, black or white. Throw the batch away and start again with more starter so the pH drops faster.

Keeping a mother between batches

A spare mother lives happily in a jar of finished vinegar, sometimes called a mother hotel. Cover it with cloth or a loose lid and keep it at room temperature, away from your other ferments. Every couple of months add a splash of wine or cider to feed it. It will keep growing new layers; peel off the oldest and discard or share them.

Watch for

  • Do not refrigerate a mother you want to keep active; cold slows the bacteria right down.
  • Keep vinegar mothers away from kombucha, sourdough and vegetable ferments. Acetic acid bacteria travel on fruit flies and can sour them.
  • A mother that has turned black, slimy and foul-smelling has died. Discard it and grow a new one from raw vinegar.

For the full process of using your mother, see how to make apple cider vinegar and how to make wine vinegar.

FAQ

Frequently asked questions

What is the mother in vinegar?
A mat of bacterial cellulose produced by acetic acid bacteria, mainly Acetobacter and Komagataeibacter species. It holds the bacteria at the surface, where they get the oxygen they need to turn alcohol into acetic acid.
Is the mother in vinegar safe to eat?
Yes. It is the same bacteria that are in the vinegar, bound in cellulose. It is rubbery and not pleasant to eat, so most people strain it out, but strands of mother in a bottle of raw vinegar are harmless.
How do I get a vinegar mother?
Mix one part raw, unpasteurized vinegar with three parts wine or hard cider in a wide jar, cover with cloth and leave it at 20–30°C. A film forms within one to three weeks and thickens into a mother. You can also get a piece from someone who makes vinegar.
Do I need a mother to make vinegar?
No. The bacteria in the liquid do most of the work. Raw vinegar on its own is a good starter, and a new mother forms by itself on every batch. A mother just gives the batch a head start.
Why did my vinegar mother sink?
Mothers get heavy as they thicken, or sink when the jar is moved. It does no harm. The bacteria will form a new film on the surface where the air is.
Is a kombucha SCOBY the same as a vinegar mother?
They are related but not the same. Both are cellulose mats made by acetic acid bacteria, but a kombucha SCOBY also carries yeasts and is adapted to sweet tea, while a vinegar mother is adapted to alcohol. A kombucha SCOBY can turn wine or cider into vinegar, though more slowly.
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