Temperature reference
63–67°F Sourdough (17.20–19.40°C)
Bulk multiplier: 1.500× · Proof multiplier: 1.550× · Activity: moderate
Dial shows where 63–67°F sits on the sourdough activity scale (32–100°F). Indicator points at the midpoint; color shifts from cool blue (dormant) to warm orange (hyperactive).
Recommendation
Cool kitchen — spring/fall without heating, air-conditioned summer. Ferment 1.5× longer than baseline. Good flavor development territory. Dough develops more complex sour notes. Manageable schedule. Extend bulk and proof by 50% vs recipe defaults.
Timing calculator at this temperature
- Multiplier at 65°F
- 1.9×
- Adjusted bulk ferment
- 7.6 h
- Adjusted final proof
- 22.8 h
How the math works
Multipliers are piecewise-linear interpolations between reference points measured by Myhrvold et al. in Modernist Bread vol 3. 76°F is the baseline (1.0×); every 10°F drop roughly doubles fermentation time, and every 10°F rise roughly halves it.
How each style behaves at this temperature
Click any style to see its full timing at 63–67°F:
- Country Loaf (Pain de Campagne)
- Ciabatta
- Baguette
- Focaccia
- Sourdough Brioche
- 100% Rye Pan Loaf
- 40% Rye Hearth Loaf
- 100% Whole Wheat Pan Loaf
- Spelt Hearth Loaf
- Pain de Campagne (Variant with Rye)
- Sourdough Bagel
- Sourdough Pretzel
- Neapolitan Pizza (Sourdough)
- NY Style Pizza (Sourdough)
- Focaccia Genovese
- Pain au Levain
- Miche (Poilâne-Style)
- Pan de Cristal
- Ciabatta Integrale
- Sourdough English Muffin
- Sourdough Naan
- Sourdough Tortilla
- Sourdough Challah
- Sourdough Panettone
- Hokkaido Milk Bread (Sourdough)
Related references on this site
- Guide: temperature and time in sourdough — the piecewise-linear multipliers and how to use them in planning
- Autolyse strategy by temperature — warmer kitchen needs shorter autolyse before adding starter
- Levain build timing — how long to wait before peak in a hot vs cold kitchen
- All 25 recipes — each has a /timing page — each recipe shows bulk + proof at 63-67°F
- All 12 hydration levels — drier doughs ferment slower; combine hydration choice with temperature
- All 8 temperature ranges — from cold retard 38-40°F to peak summer 88-95°F