Convert 75g Sourdough Starter (80% Hydration) to Commercial Yeast
How to remove 75g of 80% hydration levain from any sourdough recipe by restoring +41.7g flour and +33.3g water.
Replacing 75g of 80% hydration levain with commercial yeast requires restoring +41.7g dry flour and +33.3g water so batch mass and 70.8% True Hydration stay unchanged (491.7g total flour / 348.3g total water on a 450g base), paired with 6.9g (2.2 tsp) Instant Dry Yeast.
- Add Back Flour
- +41.7gReplaces flour inside 75g (80%) starter
- Add Back Water
- +33.3gReplaces water inside 75g (80%) starter
- Instant Yeast (2-Hr Rise)
- 6.9g (2.2 tsp)For 491.7g total flour batch
- Preserved Hydration
- 70.8%348.3g W / 491.7g F
Reverse Conversion Chart: 75g Starter → Commercial Yeast
Each row re-derives the yeast dose from total flour and the fermentation schedule rather than from the starter weight.
| Fermentation Window | Instant Yeast Grams (Teaspoons) | Active Dry Yeast Grams (Teaspoons) | Fresh Cake Yeast Grams | Flour & Water to Put Back |
|---|---|---|---|---|
| [Primary]: 55g starter at 80% | instant 6.7g | active dry 8.4g | fresh 20.2g | bake 1.5 – 2.0 hours warm bulk rise |
| Compact Read: 75g starter at 80% | instant 3.4g | active dry 4.3g | fresh 10.3g | bake 3.5 – 4.5 hours slow room-temp rise |
| Extended Read: 95g starter at 80% | instant 1.3g | active dry 1.6g | fresh 3.8g | bake 12 – 18 hours cold fermentation (39°f / 4°c) |
| Generous Read: 65g starter at 80% | instant 6.8g | active dry 8.5g | fresh 20.4g | bake 1.5 – 2.0 hours warm bulk rise |
| Lean Read: 85g starter at 80% | instant 3.5g | active dry 4.4g | fresh 10.4g | bake 3.5 – 4.5 hours slow room-temp rise |
Custom Batch Recalculation Engine
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Decomposing 75g of 80% Hydration Starter: Flour + Water Conservation
By definition, a starter hydrated at 80% contains 100 parts flour and 80 parts water. Using Flour = 75 ÷ (1 + 0.8), your 75g of starter holds 41.7g of flour and 33.3g of water.
Crust colour is a tell. A levain dough browns more slowly because its sugars are already partly consumed, so a converted dough reaches a deeper, faster colour at the same temperature and often benefits from a slightly cooler oven.
Step-by-Step Reverse Conversion Protocol (75g @ 80%)
- Plan Around the Lost Complexity: Without a levain you lose the slow acid build, so if the 75g of 80% starter was there for flavour, add a little honey or malt and a spoonful of yoghurt.
- Restore the Mass: Return 41.7g of flour and 33.3g of water to the base recipe.
- Dose the Yeast: 6.9g (2.2 tsp) of instant, 8.6g of active dry, or 20.7g of fresh cake yeast.
- Ferment, Shape, Bake: Respect the 1.5 – 2.0 hours warm bulk rise schedule, and remember the 70.8% hydration is unchanged by the swap.
Technical Q&A: Convert 75g Sourdough Starter (80% Hydration) to
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 6.9g, otherwise the 491.7g dough will over-proof.
Will my converted dough taste different from the levain version?
Yes. The roughly 2g of residual acid inside 75g 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 6.9g, otherwise the 491.7g dough will over-proof.