🌡️ Fermentation Temperature & Time Reference Chart
A quick reference for typical temperature ranges and fermentation times across common home ferments.
What the chart lists
Eight common home ferments, each with the temperature band the culture works best in and the time it usually needs there:
| Ferment | Temperature | Time |
|---|---|---|
| Kombucha, first ferment | 70-80 °F | 7-14 days |
| Kombucha, second ferment | 70-80 °F | 2-5 days |
| Sauerkraut and lacto veg | 65-75 °F | 1-4 weeks |
| Yogurt | 100-115 °F | 5-10 hours |
| Milk kefir | 68-78 °F | 18-36 hours |
| Water kefir | 68-78 °F | 24-48 hours |
| Sourdough starter | 70-80 °F | 4-8 hours between feeds |
| Kimchi | 60-70 °F | 1-5 days, then refrigerate |
Temperature and time trade against each other. Yeasts and bacteria roughly double their pace for every 18 °F of warmth, so a kombucha that is ready in seven days at 80 °F can take a fortnight at 68 °F, and milk kefir set out in a cold kitchen may still be thin after 36 hours.
Reading the ranges
- Measure the vessel, not the room. Tape a stick-on aquarium thermometer to the jar. A crock on a tiled floor can sit 5 °F below the thermostat reading.
- Yogurt is the outlier. Its 100-115 °F band needs a maker, oven light or cooler, and holding it there for the whole 5-10 hours is what sets the curd.
- Times are a window, not a deadline. Taste from day one of the range. Longer means more sour and less sugar in every ferment listed.
Frequently asked questions
How long does kombucha take to ferment?
7 to 14 days at 70-80 °F for the first ferment, then 2 to 5 days in sealed bottles for the second. The warm end of the band gives the shorter time.
What temperature does yogurt need?
100 to 115 °F for 5 to 10 hours. Below about 95 °F the cultures work too slowly to set properly; much above 120 and they stall.
My kitchen is 62 °F. Can I still ferment?
Sauerkraut and kimchi are fine at that temperature and simply take the longer end of their range. Kombucha, kefir and sourdough all want warmth, so move the jar to a cupboard near a boiler or use a seedling mat set low.