Overnight Counter Sourdough Bulk Fermentation at 66 Degrees (66°F / 19°C) with 5% Starter
LAB 3.2:1 organic acid balance and 24–31.1 hr bulk schedule for 66°F (18.9°C) doughs inoculated at 5%.
For a 66°F (18.9°C) batch seeded at 5% starter (25g per 500g flour), schedule 24–31.1 hours on the bench and fold every 45 minutes. Bench-shape strictly at +75% true volumetric expansion (+69.6% vertical height rise in a sloped bowl to 6.78 cm) so you never suffer the +141.4% volume explosion of doubling bowl height.
- Estimated Bulk Time
- 24–31.1 hrsAt 66°F (18.9°C) with 5% starter (Q10=0.51x)
- Target Aliquot Volume Rise
- +75%Capped volumetric cutoff (<43.9°F dormancy)
- Sloped Bowl Height Target
- 6.78 cm+69.6% vertical climb from 4.0 cm
- 2x Height Trap Warning
- +141.4% VolCoil fold every 45m (LAB 3.2:1)
2D Thermal & Inoculation Sensitivity Table for 66°F (18.9°C) @ 5% Levain
5-point neighborhood comparison around 66°F (18.9°C) and 5% starter (25g/500g flour), showing window hours, conical height rise %, straight-wall volume rise %, and 45-min coil fold intervals.
| Temp & Levain Seed (Around 66°F / 5%) | Fermentation Window | 9" Conical Height Rise | Straight-Wall Volume Rise | Coil Fold Cadence |
|---|---|---|---|---|
| 64°F (17.8°C) @ 3% (15g) Cooler / Lower Seed | 40.3–53.6 hrs (2418–3216m) | +71.7% height (4.0 → 6.87 cm) | +75% vol (2x trap: +146.9%) | Every 48 min (Row 1) |
| 66°F (18.9°C) @ 3% (15g) Baseline Temp / Lower Seed | 35.2–45.6 hrs (2112–2736m) | +69.6% height (4.0 → 6.78 cm) | +75% vol (2x trap: +141.4%) | Every 46 min (Row 2) |
| 66°F (18.9°C) @ 5% (25g) [Current Target] | 24–31.1 hrs (1440–1866m) | +69.6% height (4.0 → 6.78 cm) | +75% vol (2x trap: +141.4%) | Every 45 min (Row 3) |
| 66°F (18.9°C) @ 8% (40g) Baseline Temp / Higher 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 4) |
| 68°F (20°C) @ 8% (40g) Warmer / Higher Seed | 14.9–17.9 hrs (894–1074m) | +60.3% height (4.0 → 6.41 cm) | +75% vol (2x trap: +117.2%) | Every 42 min (Row 5) |
On-Bench Hydration & Fermentation Adjuster
Modify base flour mass, levain inoculation, or ambient kitchen temperature below to recalculate from this 24–31.1 hrs baseline.
Overnight Cold-Counter Kinetics at 66 Degrees (66°F / 19°C): Target +75% Rise
By integrating the conical frustum volume integral V(z) = ∫ π r(z)² dz across a 14 cm base and 24 cm rim, a +75% volumetric expansion at 66°F (18.9°C) and 5% inoculation lifts dough height by only +69.6% (from 4.0 cm to 6.78 cm). Waiting for vertical height to double during the 24–31.1 hr window creates a +141.4% volume explosion.
Conductive heat transfer from a 66°F (18.9°C) boule in a rattan banneton requires hours to reach the 43.9°F yeast-dormancy threshold. During that cooling tail, a 5% inoculation (LAB ratio 3.2:1, Q10=0.51x) adds residual lift—making the +75% cutoff (6.78 cm height, 45-min folds) mandatory.
Precision Bulk Fermentation Workflow: 66°F (18.9°C) with 25g Levain
- Seed & Thermal Check (66°F / 18.9°C): Verify dough core reads 66°F after incorporating 25g active levain (5% baker's math) for a 3.2:1 LAB balance.
- Aliquot & Sloped Vessel Setup: Place 40g dough in a straight cylinder (mark +75%) and set a ruler at 6.78 cm (+69.6% climb) on your 24 cm sloped bowl.
- Gluten Alignment (45-Min Intervals): Perform gentle folds every 45 minutes without degassing; stop folding 90 minutes before hour 24.
- Bench Preshape & 38°F Retard: Dump onto the bench between 24 and 31.1 hours at +75% rise, tension-roll, and refrigerate immediately until core drops past 43.9°F.
Common Scaling & Troubleshooting Questions (24–31.1 hrs)
How often should I do coil folds at 66°F with 5% starter?
Space your coil folds every 45 minutes during the first half of the 24–31.1 hour window at 66°F (18.9°C) so the gluten network holds its +75% rise.
What happens if my 66°F kitchen warms up by 2°F during a 5% starter bulk?
A +2°F rise to 68°F accelerates Q10 kinetics above 0.51x and shortens the 24–31.1 hr window, so monitor the 6.78 cm (+75% volume) mark closely.
What percentage rise should I look for at 66°F (18.9°C) with 5% levain?
Target +75% true volumetric expansion (+69.6% vertical height rise in a sloped bowl, from 4.0 cm to 6.78 cm) before 38°F cold retarding, avoiding the +141.4% volume explosion of doubling height.