Sourdough Bulk Fermentation Time at 75 Degrees (75°F / 24°C) with 18% Starter (+50.2% Rise)
Q10=1x metabolic curve for 90g starter per 500g flour at 75°F (23.9°C): stop at 5.53 cm bowl height (+50.2% aliquot rise).
Fermenting a 75°F (23.9°C) dough inoculated at 18% (90g active culture/500g flour) requires 4.9 to 6 hours with 30-minute coil folds. Shape at +50.2% true volumetric expansion (+38.3% vertical height rise in a sloped bowl from 4.0 cm to 5.53 cm) to avoid the +67.3% volume explosion of a 2x height trap.
- Estimated Bulk Time
- 4.9–6 hrsAt 75°F (23.9°C) with 18% starter (Q10=1x)
- Target Aliquot Volume Rise
- +50.2%Capped volumetric cutoff (<44.8°F dormancy)
- Sloped Bowl Height Target
- 5.53 cm+38.3% vertical climb from 4.0 cm
- 2x Height Trap Warning
- +67.3% VolCoil fold every 30m (LAB 5.6:1)
Conical Height vs. Aliquot Volume Matrix Centered on 75°F / 18% Starter
5-point neighborhood comparison around 75°F (23.9°C) and 18% starter (90g/500g flour), showing window hours, conical height rise %, straight-wall volume rise %, and 30-min coil fold intervals.
| Temp & Levain Seed (Around 75°F / 18%) | Fermentation Window | 9" Conical Height Rise | Straight-Wall Volume Rise | Coil Fold Cadence |
|---|---|---|---|---|
| 73°F (22.8°C) @ 16% (80g) Cooler / 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 1) |
| 75°F (23.9°C) @ 16% (80g) Baseline Temp / Lower Seed | 5.3–6.5 hrs (318–390m) | +38.5% height (4.0 → 5.54 cm) | +50.5% vol (2x trap: +67.8%) | Every 31 min (Row 2) |
| 75°F (23.9°C) @ 18% (90g) [Current Target] | 4.9–6 hrs (294–360m) | +38.3% height (4.0 → 5.53 cm) | +50.2% vol (2x trap: +67.3%) | Every 30 min (Row 3) |
| 75°F (23.9°C) @ 21% (105g) Baseline Temp / 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 4) |
| 77°F (25°C) @ 21% (105g) Warmer / Higher Seed | 3.7–4.7 hrs (222–282m) | +33.3% height (4.0 → 5.33 cm) | +43.2% vol (2x trap: +57.2%) | Every 27 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 75 Degrees (75°F / 24°C): Target +50.2% Rise
Endogenous cereal protease (aspartic proteinase) cleaves disulfide-linked glutenin macropolymers at a Q10 rate of 1x when dough sits at 75°F (23.9°C). Under a 18% levain load, extending bulk past 6 hours or beyond 5.53 cm (+38.3% height / +50.2% volume) risks irreversible slackening toward the +67.3% conical trap.
According to Henry's Law of gas solubility, chilling a 75°F (23.9°C) dough mass below 44.8°F increases aqueous CO2 absorption into the dough liquor while 18% levain yeast slows down. Shaping at 5.53 cm (+38.3% conical climb, +50.2% volume) after 4.9–6 hrs preserves spring without hitting the +67.3% trap.
4-Stage Bench & Cold-Retard Protocol for 75°F Dough at 18% Starter
- Seed & Thermal Check (75°F / 23.9°C): Verify dough core reads 75°F after incorporating 90g active levain (18% baker's math) for a 5.6:1 LAB balance.
- Aliquot & Sloped Vessel Setup: Place 40g dough in a straight cylinder (mark +50.2%) and set a ruler at 5.53 cm (+38.3% climb) on your 24 cm sloped bowl.
- Gluten Alignment (30-Min Intervals): Perform gentle folds every 30 minutes without degassing; stop folding 90 minutes before hour 4.9.
- Bench Preshape & 38°F Retard: Dump onto the bench between 4.9 and 6 hours at +50.2% rise, tension-roll, and refrigerate immediately until core drops past 44.8°F.
Frequently Asked Questions for This Bulk Fermentation Temp × Inoculation Spec
How many grams of starter is 18% inoculation for a 500g flour loaf at 75°F?
A 18% inoculation on 500g main flour equals 90g of active 100% hydration starter (45g flour + 45g water), fermenting in 4.9–6 hours at 75°F.
How do I adjust 75°F bulk time if I drop starter from 18% to 16%?
Reducing inoculation from 18% to 16% at 75°F (23.9°C) extends the 4.9–6 hr bulk window while keeping the same +50.2% volumetric (5.53 cm height) shaping target.
How many hours should sourdough bulk ferment at 75°F with 18% starter?
At 75°F (23.9°C) with 18% starter (90g per 500g flour), bulk fermentation takes 4.9 to 6 hours (Q10=1x) to reach +50.2% true volumetric expansion (+38.3% vertical height rise in a sloped bowl).