fermentation · how long does
How long does apple cider vinegar take to ferment?
Apple cider vinegar takes 6–12 weeks to ferment from fresh cider. First phase: cider → alcohol (2–4 weeks). Second phase: alcohol → vinegar (4–8 weeks).
The full answer
Apple cider vinegar fermentation has two distinct phases. First, yeasts convert apple sugars to alcohol (essentially making hard cider). Second, Acetobacter bacteria convert the alcohol to acetic acid (the vinegar component).
Phase 1 — Alcoholic fermentation: 2–4 weeks - Wild yeasts or added Saccharomyces convert sugars to ~5–7% alcohol - Visible bubbling for 1–2 weeks, then slows - Tastes like hard cider when complete
Phase 2 — Acetic fermentation: 4–8 weeks - Acetobacter (often introduced via a "mother" or unpasteurized vinegar) converts alcohol to acetic acid - Forms gelatinous "mother of vinegar" on surface (normal — culture it for next batch) - Vinegar smell develops gradually; sharp + sour when complete - pH drops to 2.5–3.0
Total: 6–12 weeks for raw apple cider vinegar with mother. Commercial fast-process ACV (Bragg's, etc.) uses controlled bioreactors and finishes in days.
Temperature: 60–80°F (15–27°C) is ideal. Cooler stalls; warmer rushes and risks off-flavors.
The vinegar is done when pH tests below 4.0 and taste is sharply sour without alcoholic note. Then strain (keep mother for next batch) and bottle. Stores indefinitely.
Don't tightly seal during fermentation — Acetobacter is aerobic; needs oxygen. Use a cloth cover or loosely-fitted lid.
Time ranges by condition
| Condition | Duration | Note |
|---|---|---|
| From fresh apple cider (60–70°F) | 8–12 weeks total | — |
| From hard cider, starting at alcoholic phase | 4–8 weeks | — |
| Warm fermentation (75–80°F) | 5–7 weeks | Faster but watch for harsh acidity |
What changes the time
- Starting sugar content. Higher sugar → higher alcohol → stronger vinegar; standard cider is ~12% sugar
- Mother of vinegar present. Adding existing mother accelerates phase 2 by ~50%
- Oxygen access. Acetobacter is aerobic; cover with cloth, not airtight lid
- Pasteurization. Pasteurized juice = no wild yeasts; need to add starter (not optional)
Common questions
What is the "mother" of vinegar?
A gelatinous biofilm of Acetobacter bacteria that forms during fermentation. It's safe, edible, and reusable — strain it out, save it in a jar of vinegar, and use it to start your next batch (cuts fermentation time ~50%).
Can I use any apples for vinegar?
Yes, but a mix of sweet and tart apples produces best flavor (just like cider). Scraps + cores work for "scrap vinegar" — a sustainability-friendly method that produces lighter vinegar.
How do I know when vinegar is done?
Taste it — should be sharp + sour with no alcohol note. pH test strips should read below 4.0 (ideally 2.5–3.5). Visual: mother on surface, cloudy liquid below.
Sources
We cite primary research, expert practice, and authoritative reference. Higher-tier sources weighted heavier. See methodology.
- Sandor Katz, "The Art of Fermentation" — Detailed two-phase vinegar fermentation framework
- NCHFP vinegar guide — Food-safety guidance for home vinegar making
- Andrew Schloss, "Cooking Slow" — Home cider-to-vinegar timeline with practical tips
- Cornell Cider & Vinegar extension materials — Commercial vs home vinegar process; pH and acidity testing
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Other earned-pages on AskedWell with similar mechanism.
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- How long do fermented pickles take? — Fermented pickles (sour pickles, deli-style) take 1–4 weeks at room temperature.
- How long does yogurt take to ferment? — Yogurt typically takes 4–8 hours at 110°F (43°C) to ferment.
Last verified: 2026-05-20 · Published 2026-05-20
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