Sourdough Bulk Fermentation Time at 73 Degrees (73°F / 23°C) with 25% Starter (+59.3% Rise)
Avoiding the +80.9% conical height trap at 73°F (22.8°C) with 25% starter (4.4–5.5 hrs to +59.3% rise).
With 25% levain (125g/500g flour) at 73°F (22.8°C), microbial CO2 production (LAB ratio 5.5:1) reaches shaping readiness in 4.4–5.5 hours. Target +59.3% true volumetric expansion (+44.7% vertical height rise in a sloped bowl, hitting 5.79 cm) before 38°F cold retarding—waiting for doubled vertical height triggers a +80.9% volume explosion.
- Estimated Bulk Time
- 4.4–5.5 hrsAt 73°F (22.8°C) with 25% starter (Q10=0.86x)
- Target Aliquot Volume Rise
- +59.3%Capped volumetric cutoff (<44.3°F dormancy)
- Sloped Bowl Height Target
- 5.79 cm+44.7% vertical climb from 4.0 cm
- 2x Height Trap Warning
- +80.9% VolCoil fold every 30m (LAB 5.5:1)
Conical Height vs. Aliquot Volume Matrix Centered on 73°F / 25% Starter
5-point neighborhood comparison around 73°F (22.8°C) and 25% starter (125g/500g flour), showing window hours, conical height rise %, straight-wall volume rise %, and 30-min coil fold intervals.
| Temp & Levain Seed (Around 73°F / 25%) | Fermentation Window | 9" Conical Height Rise | Straight-Wall Volume Rise | Coil Fold Cadence |
|---|---|---|---|---|
| 71°F (21.7°C) @ 23% (115g) Cooler / Lower Seed | 5.4–6.8 hrs (324–408m) | +50.8% height (4.0 → 6.03 cm) | +68.2% vol (2x trap: +94.6%) | Every 33 min (Row 1) |
| 73°F (22.8°C) @ 23% (115g) Baseline Temp / Lower Seed | 4.7–5.9 hrs (282–354m) | +44.9% height (4.0 → 5.8 cm) | +59.6% vol (2x trap: +81.3%) | Every 31 min (Row 2) |
| 73°F (22.8°C) @ 25% (125g) [Current Target] | 4.4–5.5 hrs (264–330m) | +44.7% height (4.0 → 5.79 cm) | +59.3% vol (2x trap: +80.9%) | Every 30 min (Row 3) |
| 73°F (22.8°C) @ 28% (140g) Baseline Temp / Higher Seed | 4–5.1 hrs (240–306m) | +44.3% height (4.0 → 5.77 cm) | +58.8% vol (2x trap: +80.1%) | Every 29 min (Row 4) |
| 75°F (23.9°C) @ 28% (140g) Warmer / Higher Seed | 3.5–4.3 hrs (210–258m) | +37.4% height (4.0 → 5.5 cm) | +49% vol (2x trap: +65.6%) | Every 27 min (Row 5) |
On-Bench Hydration & Fermentation Adjuster
Modify base flour mass, levain inoculation, or ambient kitchen temperature below to recalculate from this 4.4–5.5 hrs baseline.
When to Stop Bulk Fermentation at 73 Degrees (73°F / 23°C): Target +59.3% Rise
Arrhenius Q10 kinetics at 73°F (22.8°C) scale wild yeast metabolic velocity by 0.86x relative to a 75°F baseline. With a 25% starter seed (125g levain per 500g flour), exponential log-phase budding spans 4.4 to 5.5 hours, requiring coil folds every 30 minutes before reaching the +59.3% volumetric cutoff (5.79 cm in a sloped bowl).
Conductive heat transfer from a 73°F (22.8°C) boule in a rattan banneton requires hours to reach the 44.3°F yeast-dormancy threshold. During that cooling tail, a 25% inoculation (LAB ratio 5.5:1, Q10=0.86x) adds residual lift—making the +59.3% cutoff (5.79 cm height, 30-min folds) mandatory.
Managing a 73°F (22.8°C) / 25% Inoculation Sourdough Schedule
- Starter Dispersion (125g per 500g Flour): Pinch 25% ripe starter into the autolysed mass at 73°F (22.8°C), establishing a 0.86x metabolic rate.
- Scheduled Strengthening (Every 30 Mins): Lift and tuck the dough every 30 minutes to balance the 5.5:1 lactic-to-acetic acid curve.
- Geometric Termination (+59.3% Volume): End bulk between 4.4 and 5.5 hrs once vertical height reaches 5.79 cm (+44.7%), avoiding the +80.9% 2x-height blowout.
- Cold-Shelf Transfer (44.3°F Cutoff): Seal the shaped loaf in a floured liner and place on the bottom 37°F–38°F fridge shelf to arrest yeast below 44.3°F.
Common Scaling & Troubleshooting Questions (4.4–5.5 hrs)
How many grams of starter is 25% inoculation for a 500g flour loaf at 73°F?
A 25% inoculation on 500g main flour equals 125g of active 100% hydration starter (63g flour + 63g water), fermenting in 4.4–5.5 hours at 73°F.
When should I stop stretching and folding a 73°F dough with 25% starter?
Complete your 30-minute coil fold sets within the first 2.6 hours at 73°F (22.8°C), leaving the final stretch undisturbed until the dough reaches 5.79 cm (+59.3% volume).
What percentage rise should I look for at 73°F (22.8°C) with 25% levain?
Target +59.3% true volumetric expansion (+44.7% vertical height rise in a sloped bowl, from 4.0 cm to 5.79 cm) before 38°F cold retarding, avoiding the +80.9% volume explosion of doubling height.