Sourdough Bulk Fermentation Time at 73 Degrees (73°F / 23°C) with 18% Starter (+60.3% Rise)
Q10=0.86x metabolic curve for 90g starter per 500g flour at 73°F (22.8°C): stop at 5.82 cm bowl height (+60.3% aliquot rise).
For a 73°F (22.8°C) batch seeded at 18% starter (90g per 500g flour), schedule 5.6–7 hours on the bench and fold every 33 minutes. Bench-shape strictly at +60.3% true volumetric expansion (+45.4% vertical height rise in a sloped bowl to 5.82 cm) so you never suffer the +82.4% volume explosion of doubling bowl height.
- Estimated Bulk Time
- 5.6–7 hrsAt 73°F (22.8°C) with 18% starter (Q10=0.86x)
- Target Aliquot Volume Rise
- +60.3%Capped volumetric cutoff (<44.5°F dormancy)
- Sloped Bowl Height Target
- 5.82 cm+45.4% vertical climb from 4.0 cm
- 2x Height Trap Warning
- +82.4% VolCoil fold every 33m (LAB 5.2:1)
Bulk Fermentation Time & Bowl Geometry Matrix Around 73°F (22.8°C) & 18% Starter
5-point neighborhood comparison around 73°F (22.8°C) and 18% starter (90g/500g flour), showing window hours, conical height rise %, straight-wall volume rise %, and 33-min coil fold intervals.
| Temp & Levain Seed (Around 73°F / 18%) | Fermentation Window | 9" Conical Height Rise | Straight-Wall Volume Rise | Coil Fold Cadence |
|---|---|---|---|---|
| 71°F (21.7°C) @ 16% (80g) Cooler / Lower Seed | 7.1–8.9 hrs (426–534m) | +51.6% height (4.0 → 6.06 cm) | +69.4% vol (2x trap: +96.4%) | Every 36 min (Row 1) |
| 73°F (22.8°C) @ 16% (80g) Baseline Temp / Lower Seed | 6.1–7.7 hrs (366–462m) | +45.6% height (4.0 → 5.82 cm) | +60.6% vol (2x trap: +82.8%) | Every 33 min (Row 2) |
| 73°F (22.8°C) @ 18% (90g) [Current Target] | 5.6–7 hrs (336–420m) | +45.4% height (4.0 → 5.82 cm) | +60.3% vol (2x trap: +82.4%) | Every 33 min (Row 3) |
| 73°F (22.8°C) @ 21% (105g) Baseline Temp / Higher Seed | 5–6.3 hrs (300–378m) | +45.1% height (4.0 → 5.8 cm) | +59.9% vol (2x trap: +81.8%) | Every 32 min (Row 4) |
| 75°F (23.9°C) @ 21% (105g) Warmer / Higher Seed | 4.3–5.3 hrs (258–318m) | +38.1% height (4.0 → 5.52 cm) | +49.9% vol (2x trap: +66.9%) | Every 29 min (Row 5) |
Interactive Bulk Fermentation Temp × Inoculation Calculator
Compare your exact mixing bowl dimensions, flour protein percentage, or discard weight in real time.
When to Stop Bulk Fermentation at 73 Degrees (73°F / 23°C): Target +60.3% 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 +60.3% volumetric expansion at 73°F (22.8°C) and 18% inoculation lifts dough height by only +45.4% (from 4.0 cm to 5.82 cm). Waiting for vertical height to double during the 5.6–7 hr window creates a +82.4% volume explosion.
Surface tension generated during shaping at 73°F (22.8°C) must withstand both 18% levain gas pressure and the cooling transition to 44.5°F. By capping bulk at +60.3% volumetric expansion (5.82 cm / +45.4% height at 5.6–7 hrs) with 33-min folds, blisters form cleanly without collapsing.
4-Stage Bench & Cold-Retard Protocol for 73°F Dough at 18% Starter
- Formula Seeding (90g Starter / 73°F): Fold 18% active starter into your 500g main flour dough at 73°F (22.8°C) (Q10 factor 0.86x).
- Interval Folding (33 Mins Apart): Apply wet-hand coil folds every 33 minutes to reinforce disulfide cross-links during the 5.6–7 hr bulk.
- Conical Frustum Inspection (5.82 cm): Verify a +45.4% vertical rise (4.0 → 5.82 cm, equal to +60.3% volume) rather than risking a +82.4% 2x height explosion.
- Cold Proofing Arrest (<44.5°F): Pre-shape, rest 20 min, final-shape, and load into a 38°F fridge so fermentation tapers off below 44.5°F.
Frequently Asked Questions for This Bulk Fermentation Temp × Inoculation Spec
When should I stop stretching and folding a 73°F dough with 18% starter?
Complete your 33-minute coil fold sets within the first 3.4 hours at 73°F (22.8°C), leaving the final stretch undisturbed until the dough reaches 5.82 cm (+60.3% volume).
How many grams of starter is 18% inoculation for a 500g flour loaf at 73°F?
A 18% inoculation on 500g main flour equals 90g of active 100% hydration starter (45g flour + 45g water), fermenting in 5.6–7 hours at 73°F.
What percentage rise should I look for at 73°F (22.8°C) with 18% levain?
Target +60.3% true volumetric expansion (+45.4% vertical height rise in a sloped bowl, from 4.0 cm to 5.82 cm) before 38°F cold retarding, avoiding the +82.4% volume explosion of doubling height.