Overnight Counter Sourdough Bulk Fermentation at 66 Degrees (66°F / 19°C) with 10% Starter
Q10=0.51x metabolic curve for 50g starter per 500g flour at 66°F (18.9°C): stop at 6.76 cm bowl height (+75% aliquot rise).
Under 66°F (18.9°C) thermal kinetics (Q10=0.51x) and 10% starter (50g/500g), bulk spans 14.3–18.5 hours with a 3.4:1 lactic-to-acetic profile. Terminate fermentation at +75% true volumetric expansion (+68.9% vertical height rise in a sloped bowl to 6.76 cm), preventing the +139.5% volume explosion of a 2x vertical climb.
- Estimated Bulk Time
- 14.3–18.5 hrsAt 66°F (18.9°C) with 10% starter (Q10=0.51x)
- Target Aliquot Volume Rise
- +75%Capped volumetric cutoff (<43.8°F dormancy)
- Sloped Bowl Height Target
- 6.76 cm+68.9% vertical climb from 4.0 cm
- 2x Height Trap Warning
- +139.5% VolCoil fold every 44m (LAB 3.4:1)
2D Thermal & Inoculation Sensitivity Table for 66°F (18.9°C) @ 10% Levain
5-point neighborhood comparison around 66°F (18.9°C) and 10% starter (50g/500g flour), showing window hours, conical height rise %, straight-wall volume rise %, and 44-min coil fold intervals.
| Temp & Levain Seed (Around 66°F / 10%) | Fermentation Window | 9" Conical Height Rise | Straight-Wall Volume Rise | Coil Fold Cadence |
|---|---|---|---|---|
| 64°F (17.8°C) @ 8% (40g) Cooler / Lower Seed | 19.3–25.7 hrs (1158–1542m) | +71.7% height (4.0 → 6.87 cm) | +75% vol (2x trap: +146.9%) | Every 47 min (Row 1) |
| 66°F (18.9°C) @ 8% (40g) Baseline Temp / Lower Seed | 16.9–21.9 hrs (1014–1314m) | +69.2% height (4.0 → 6.77 cm) | +75% vol (2x trap: +140.2%) | Every 44 min (Row 2) |
| 66°F (18.9°C) @ 10% (50g) [Current Target] | 14.3–18.5 hrs (858–1110m) | +68.9% height (4.0 → 6.76 cm) | +75% vol (2x trap: +139.5%) | Every 44 min (Row 3) |
| 66°F (18.9°C) @ 13% (65g) Baseline Temp / Higher Seed | 11.7–15.2 hrs (702–912m) | +68.5% height (4.0 → 6.74 cm) | +75% vol (2x trap: +138.3%) | Every 43 min (Row 4) |
| 68°F (20°C) @ 13% (65g) Warmer / Higher Seed | 10.4–12.4 hrs (624–744m) | +59.6% height (4.0 → 6.38 cm) | +75% vol (2x trap: +115.6%) | Every 40 min (Row 5) |
On-Bench Hydration & Fermentation Adjuster
Modify base flour mass, levain inoculation, or ambient kitchen temperature below to recalculate from this 14.3–18.5 hrs baseline.
Overnight Cold-Counter Kinetics at 66 Degrees (66°F / 19°C): Target +75% Rise
Symbiotic lag-phase duration for 10% starter (50g/500g flour) at 66°F (18.9°C) is governed by a 0.51x thermal multiplier and a 3.4:1 lactic/acetic trajectory. Once the dough climbs +68.9% vertically to 6.76 cm (+75% aliquot volume) between 14.3 and 18.5 hours, yeast dormancy must be induced below 43.8°F.
Conductive heat transfer from a 66°F (18.9°C) boule in a rattan banneton requires hours to reach the 43.8°F yeast-dormancy threshold. During that cooling tail, a 10% inoculation (LAB ratio 3.4:1, Q10=0.51x) adds residual lift—making the +75% cutoff (6.76 cm height, 44-min folds) mandatory.
Managing a 66°F (18.9°C) / 10% Inoculation Sourdough Schedule
- Quantitative Weigh-In (10% Seed): Measure 50g bubbly 100% starter into your 500g flour batch and confirm a 66°F (18.9°C) post-mix temperature.
- Timed Coil-Fold Window (44 Mins): Space 3 to 4 coil folds at 44-minute intervals while Q10=0.51x kinetics build alveolar tension.
- Sloped-Bowl Readout (6.76 cm Target): Watch for domed shoulders at 14.3–18.5 hrs when bowl depth climbs +68.9% to 6.76 cm (+75% true volume).
- Overnight Retardation (<43.8°F): Shape with minimal flour and cold-proof 12–16 hours at 38°F as core temperature crosses the 43.8°F dormancy line.
Common Scaling & Troubleshooting Questions (14.3–18.5 hrs)
How does 10% starter affect sourness and lactic-to-acetic ratio at 66°F?
Fermenting with 10% levain at 66°F (18.9°C) produces an estimated 3.4:1 lactic-to-acetic organic acid ratio across 14.3–18.5 hours before shaping at +75% rise.
How many hours should sourdough bulk ferment at 66°F with 10% starter?
At 66°F (18.9°C) with 10% starter (50g per 500g flour), bulk fermentation takes 14.3 to 18.5 hours (Q10=0.51x) to reach +75% true volumetric expansion (+68.9% vertical height rise in a sloped bowl).
Can I cold-retard a 66°F (10% starter) dough for 16 hours after bulk?
Yes—provided you terminate bench fermentation at +75% true volumetric expansion (6.76 cm sloped height) after 14.3–18.5 hrs so thermal carryover to 43.8°F does not overproof the gluten.