Fermentation Predictor

Fermentation speed is governed mostly by temperature and slowed by salt. This tool estimates how far along a vegetable ferment is, and roughly how many days remain, so you know when to start tasting.

ProductSauerkrautKimchiCucumber pickleHot sauce mashGiardiniera

Temperature (°C)

70 °F

Salt (% by weight)

In range

Days elapsed

32%

estimated progress

Early — keep fermenting

22d

est. days to ready

0.96×

rate vs 21 °C

Estimate only — a Q10≈2 guide (rate roughly doubles per +10 °C), braked by salt. It is not a safety timer. Confirm readiness by taste and pH: a finished lacto-ferment should be pleasantly sour and below pH 4.0. Keep everything under the brine at 18–22 °C.

The model

Rate scales with temperature on a Q10 ≈ 2 rule — it roughly doubles for every +10 °C — and is braked as salt rises above the 2 % baseline. “Ready” is anchored to each product’s typical window (e.g. sauerkraut 14–28 days, kimchi 3–14 days at 21 °C).

Caution

This is an estimate, not a safety timer. Confirm a ferment is done by taste and pH, not by the clock — a finished lacto-ferment should be pleasantly sour and below pH 4.0. Under-salting or fermenting too warm are safety problems, not just quality ones.

Note

Hold vegetable ferments at 18–22 °C / 64–72 °F. When the flavor is where you want it, move the jar to the refrigerator (2–4 °C) to arrest the ferment and hold it there.