How to Convert 200g Stiff Sourdough Starter (50% Hydration) to Commercial Yeast
Restoring +133.3g flour and +66.7g water when replacing 200g of 50% stiff levain with dry or fresh yeast.
Converting 200g of 50% starter to yeast in one line: restore 133.3g of flour and 66.7g of water to the main dough, yielding 583.3g of flour and 381.7g of liquid at 65.4% true hydration, then dose 8.2g (2.6 tsp) of instant yeast for a 1.5 – 2.0 hours warm bulk rise.
- Add Back Flour
- +133.3gReplaces flour inside 200g (50%) starter
- Add Back Water
- +66.7gReplaces water inside 200g (50%) starter
- Instant Yeast (2-Hr Rise)
- 8.2g (2.6 tsp)For 583.3g total flour batch
- Preserved Hydration
- 65.4%381.7g W / 583.3g F
Reverse Conversion Chart: 200g Starter → Commercial Yeast
The restoration column shows the flour and water that must go back into the main mix to keep the 65.4% hydration intact.
| Proofing Plan | Instant Dry Yeast | Active Dry Yeast | Fresh Compressed Yeast | Dough Restoration |
|---|---|---|---|---|
| 220g @ 50% (Standard Same-Day (1.5–2 hrs)) [Primary] | 8.4g (2.7 tsp) | 10.4g (3.4 tsp) | 25.1g | +146.7g F & +73.3g W |
| 200g @ 50% (Slow Artisan Bulk (3.5–4.5 hrs)) Compact Read | 4.1g (1.3 tsp) | 5.1g (1.6 tsp) | 12.3g | +133.3g F & +66.7g W |
| 180g @ 50% (Overnight No-Knead / Cold Proof (12–18 hrs)) Extended Read | 1.4g (0.5 tsp) | 1.8g (0.6 tsp) | 4.3g | +120g F & +60g W |
| 210g @ 50% (Standard Same-Day (1.5–2 hrs)) Generous Read | 8.3g (2.7 tsp) | 10.3g (3.3 tsp) | 24.8g | +140g F & +70g W |
| 190g @ 50% (Slow Artisan Bulk (3.5–4.5 hrs)) Lean Read | 4g (1.3 tsp) | 5g (1.6 tsp) | 12.1g | +126.7g F & +63.3g W |
Dynamic Stoichiometric Workbench (+133.3g)
Test custom loaf weights or alternative fermentation schedules directly against the +66.7g benchmark above.
Decomposing 200g of 50% Stiff Levain: High-Flour Mass Conservation
Bread-machine and no-knead schedules suit this conversion particularly well. Without a levain to manage, the 583.3g / 381.7g dough and its 8.2g of yeast can be programmed once and repeated without a single judgement call about starter readiness.
If the original recipe contained a preferment as well as the levain, resolve its yeast separately. A 200 g levain accounts for its own 8.2g equivalent, and any poolish or biga on top of that is additional leavening that must be subtracted from the 8.2g.
Step-by-Step Reverse Conversion Protocol (200g @ 50%)
- Audit the Original Formula: Confirm the formula's yeast was the only leavening, and that the 200g of 50% starter was the sole source of the 133.3g of hidden flour.
- Rebuild at Full Scale: The dough is now 583.3g flour and 381.7g liquid — the same numbers as before, minus the starter.
- Dose for the Schedule You Want: 8.2g (2.6 tsp) of instant yeast for a 1.5 – 2.0 hours warm bulk rise; use about a fifth of that for a cold overnight ferment.
- Bake and Compare: The crumb will be lighter and less acid-forward, but the volume and crust colour should be close to the levain original.
Key Baker's Math Questions (Add Back Flour: +133.3g)
Can I scale the conversion to a different grain weight?
Yes. The yeast dose is a percentage of total grain, so on a larger batch multiply 8.2g by the ratio of the new grain weight to 583.3g.
Will my converted dough taste different from the levain version?
Yes. The roughly 4g of residual acid inside 200 grams of starter was providing both flavour and tenderising, and commercial yeast replaces neither.
Can I convert a dough that also contains a poolish or preferment?
Yes, but count the preferment's yeast separately and subtract it from the 8.2g, otherwise the 583.3g dough will over-proof.