Extreme 90% Hydration Sourdough (400g Flour): 320g Base + 36g Bassinage (1 Small Boule)
Ciabatta-style 90% formula on 400g flour (845g batch) with 36g bassinage staging and -4g starter deduction.
In a 400g flour formula at 90%, naive baker's math (360g water + 80g starter) overshoots to 90.9% (+0.9% above spec) across 440g total flour. Setting your scale to 356g water (-4g deduction) and 8.8g salt in a 845g batch locks True Total Hydration at 90.0% (target 90%).
- Strict True Hydration Water
- 356gLocks True Total Hydration at 90.0% (target 90%, -4g)
- Unadjusted Apparent Water
- 360gPushes True Hydration to 90.9% (+0.9% surge)
- 20% Active Starter & Salt
- 80g / 8.8g40g hidden flour + 40g hidden water
- Stickiness & Rheology
- 5 / 5 StarsExtreme / Wet Handling (Extreme extensibility)
400g Flour at 90% Hydration: 2D Scale & Starter Sensitivity Matrix
Comparing 356g corrected water (-4g cut) against 360g apparent water (90.9% drift) on 400g flour.
| Batch & Seed Spec | Flour Breakdown | Levain Split | Corrected Water (90% Ref) | Salt & Dough Mass | Apparent vs Locked |
|---|---|---|---|---|---|
| 350g @ 88% (15% Seed) Compact Mix (-50g) | 350g + 27g = 377g (90%/400g ref) | 53g (27gF/26gW @ 100%) | 306g W (vs 308g app @ R1) | 7.5g salt (709g dough) | 88.6% drift → 88.06% (88% goal) |
| 400g @ 88% (18% Seed) Conservative Pour | 400g + 40g = 440g (90%/400g ref) | 72g (40gF/32gW @ 80%) | 355g W (vs 352g app @ R2) | 8.8g salt (827g dough) | 87.3% drift → 87.95% (88% goal) |
| 400g @ 90% (20% Seed) [Locked Benchmark] | 400g + 40g = 440g (90%/400g ref) | 80g (40gF/40gW @ 100%) | 356g W (vs 360g app @ R3) | 8.8g salt (836g dough) | 90.9% drift → 90.0% (90% goal) |
| 400g @ 92% (22% Seed) Open-Crumb Push | 400g + 44g = 444g (90%/400g ref) | 88g (44gF/44gW @ 100%) | 364g W (vs 368g app @ R4) | 8.9g salt (852g dough) | 92.8% drift → 91.89% (92% goal) |
| 450g @ 92% (25% Seed) Expanded Loaf (+50g) | 450g + 50g = 500g (90%/400g ref) | 113g (50gF/63gW @ 125%) | 397g W (vs 414g app @ R5) | 10.0g salt (960g dough) | 95.4% drift → 92.0% (92% goal) |
Dynamic Stoichiometric Workbench (356g)
Test custom loaf weights or alternative fermentation schedules directly against the 360g benchmark above.
Bassinage Mechanics for 400g Flour at 90% Hydration (356g Water)
Hydrating 400g flour with 360g water plus 80g starter forces 440g total flour to absorb 400g water (90.9%). Staging 320g autolyse water and 36g bassinage water (356g total, -4g deduction) with 8.8g salt in your 845g dough locks True Total Hydration at 90.0% (target 90%).
When 400g flour is mixed to 90% (90.0%) using 356g water, 80g levain, and 8.8g salt (845g total), reserving 36g water from the 320g autolyse keeps dough stickiness at 5/5 instead of drifting to 90.9%.
Rheological Handling Guide (5/5 Tack) for 400g Flour at 90%
- Endosperm Saturation (400g Flour / 320g Water): Rub 320g water into 400g flour (saving 36g of 356g) and rest 40 min.
- Ionic Salt & Culture Mix (80g Levain + 8.8g Sea Salt): Pinch 80g peaked starter and 8.8g salt dissolved in 36g water into the 845g batch (-4g vs 360g).
- Rheological Laminations (90% / 90.0%): Perform 1 bench lamination plus 3 coil folds every 35 min for slack tenacity across 440g system flour.
- Cold Proof & Dutch Oven Spring (845g): Preshape at +50% expansion, stitch into a banneton for 12–16 hrs at 38°F, score at 45°, and bake at 450°F.
Key Baker's Math Questions (Strict True Hydration Water: 356g)
Should I use slap-and-fold or coil folds for 400g flour at 90% (356g water)?
With 356g water (320g + 36g) and 80g starter on 400g flour (845g batch, 5/5 tack), use 4 damp-hand coil folds 30 minutes apart to align the 440g flour network.
What baking temperature works best for a 845g loaf (400g flour @ 90%)?
Bake your 845g (1 Small Boule) dough made from 400g flour, 356g water (90.0%), 80g starter, and 8.8g salt in a preheated 450°F (232°C) Dutch oven for 20 min covered + 22 min uncovered.
How much water do I deduct for 80g starter in a 400g / 90% recipe?
Deduct 4g of water from the 360g apparent weight (pouring 356g main water instead) to offset the +0.9% surge (90.9%) from 80g starter (40gW/40gF).