Fermentation Time Calculator

Sauerkraut, kimchi, kombucha, sourdough: time depends on temperature; Q10 rule applies.

Inputs

Result

Fermentation window
9.3d – 19.4d
Adjusted for 70°F (reference 68°F).
  • Fermentsauerkraut
  • Reference temp68°F
  • Your temp70°F
  • Factor0.93×
  • Min time9.3d
  • Max time19.4d
  • Taste checkAlways taste — visual cues unreliable.

Step-by-step

  1. Reference range at 68°F: 10.0d - 21.0d.
  2. Q10 factor for 70°F = 0.93.
  3. Adjusted: 9.3d – 19.4d.

How to use this calculator

  • Pick ferment.
  • Enter your kitchen / fermentation temp.
  • Read window.
  • Taste at the start of the window; refrigerate when satisfied.

About this calculator

Lacto-fermentation (sauerkraut, kimchi, lacto-pickles) is driven by lactobacillus, which doubles roughly every 18°F. Yogurt is thermophilic — runs at 100-115°F to favor specific cultures. Kombucha SCOBY likes 72-78°F. The "is it done?" question always ends with taste — visual cues are unreliable. Acid production stops once pH drops below 4.6 (preserved indefinitely in fridge). Trust your nose: fermentation gone wrong smells distinctly off (rotting, ammonia) — toss it.

Frequently asked

Taste. Sauerkraut: tangy not vinegary, satisfying crunch. Kimchi: sour funk. Kombucha: lightly tart, no remaining sweetness if dry-style.

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