Fermentation Time & Temperature Calculator

Fermentation Temperature Guide

Q10 Temperature Coefficient

The Q10 value describes how much faster a biological reaction runs for each 10°C increase in temperature. For most fermentation: Q10 ≈ 2-3 (reaction rate doubles or triples per 10°C rise). Adjusted time = reference time / Q10^((actual_temp − reference_temp)/10). Example: ale fermentation at 20°C takes 72 hours. At 15°C (5°C cooler), Q10 = 2: adjusted time = 72 / 2^(−5/10) = 72 / 2^(−0.5) = 72 / 0.707 = 101 hours. At 25°C: time = 72 / 2^(5/10) = 72 / 1.414 = 51 hours. This relationship explains w

Ale vs Lager Temperature

Ale yeast (top-fermenting, Saccharomyces cerevisiae): optimal 18-24°C. At lower temperatures: stress and off-flavour production. At higher temperatures: fusel alcohols and esters (fruitiness can be intentional). UK ales typically ferment at 18-20°C. Lager yeast (bottom-fermenting, S. pastorianus): optimal 8-14°C. Extended lagering (conditioning) at near-freezing (0-2°C) for 4-8 weeks. Results in crisp, clean flavour. Cold-side fermentation control requires a temperature-controlled fermentation c

Sourdough Fermentation Control

Sourdough fermentation involves both wild yeast (CO₂ production, leavening) and lactic acid bacteria (LAB: acetic and lactic acid production). Temperature affects the yeast/LAB balance: warm (26-32°C): faster, more lactic acid, milder sourness. Cool (16-20°C): slower, more acetic acid, more complex sharper flavour. Cold retard (4-8°C): very slow, mostly LAB activity, deep sour complex flavour, extended scheduling flexibility. The inoculation rate (amount of starter) and temperature together dete

Signs of Fermentation Progress

Beer: visible CO₂ bubbling through airlock. Foam (krausen) forming on top. Hydrometer shows dropping specific gravity (SG). Final gravity (FG) reached when SG stabilises over 2-3 consecutive days. Wine: similar but CO₂ production may be less dramatic in early stages. Sourdough: levain/starter doubles in volume. Alveogram (bubble) pattern shows activity. Bulk ferment complete when dough has increased 50-75% in volume with visible bubbles. Off-fermentation signs: unusual smell (vinegar rather than