Convert 100g Sourdough Starter (80% Hydration) to Commercial Yeast
How to remove 100g of 80% hydration levain from any sourdough recipe by restoring +55.6g flour and +44.4g water.
When removing 100g of 80% hydration sourdough starter from a recipe, add back the 55.6g of grain and 44.4g of water contained inside the starter. In a 450g grain + 315g water sourdough recipe, your restored main dough becomes 505.6g grain and 359.4g water (71.1% True Hydration), leavened with 7.1g (2.3 tsp) of Instant Yeast for a 2-hour rise.
- Add Back Flour
- +55.6gReplaces flour inside 100g (80%) starter
- Add Back Water
- +44.4gReplaces water inside 100g (80%) starter
- Instant Yeast (2-Hr Rise)
- 7.1g (2.3 tsp)For 505.6g total flour batch
- Preserved Hydration
- 71.1%359.4g W / 505.6g F
Sourdough-to-Yeast Conversion Table: 100g at 80% Hydration
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 |
|---|---|---|---|---|
| [Your Batch]: 80g starter at 80% | instant 6.9g | active dry 8.7g | fresh 20.8g | bake 1.5 – 2.0 hours warm bulk rise |
| Scaled Down: 100g starter at 80% | instant 3.5g | active dry 4.4g | fresh 10.6g | bake 3.5 – 4.5 hours slow room-temp rise |
| Scaled Up: 120g starter at 80% | instant 1.3g | active dry 1.6g | fresh 3.9g | bake 12 – 18 hours cold fermentation (39°f / 4°c) |
| Trimmed: 90g starter at 80% | instant 7g | active dry 8.8g | fresh 21g | bake 1.5 – 2.0 hours warm bulk rise |
| Expanded: 110g starter at 80% | instant 3.6g | active dry 4.5g | fresh 10.7g | bake 3.5 – 4.5 hours slow room-temp rise |
Interactive Sourdough → Yeast Reverse Conversion Calculator
Compare your exact mixing bowl dimensions, flour protein percentage, or discard weight in real time.
Decomposing 100g of 80% Hydration Starter: Flour + Water Conservation
Salt interacts with the change. A levain dough was usually formulated for a 2% salt dough, and swapping in 7.1g of commercial yeast on the same 505.6g of flour keeps that salt level, which is a sensible place to leave the formula alone.
If the original recipe contained a preferment as well as the levain, resolve its yeast separately. A 100g levain accounts for its own 7.1g equivalent, and any poolish or biga on top of that is additional leavening that must be subtracted from the 7.1g.
Step-by-Step Reverse Conversion Protocol (100g @ 80%)
- Weigh the Restoration (55.6g + 44.4g): Set out the flour and water that were hiding inside the 100g of 80% starter before you do anything else.
- Build the Dough (505.6g F / 359.4g W): Combine them with the original 450g and 315g, then add 2% salt and 7.1g of instant yeast.
- Mix and Rest: Knead to a smooth, cohesive dough and rest 10 minutes before a second mix to develop gluten.
- Proof for 1.5 – 2.0 hours warm bulk rise: Bulk at 78°F (26°C) until doubled, then shape, pan and bake immediately.
Frequently Asked Questions for This Sourdough → Yeast Reverse Conversion Spec
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 7.1g, otherwise the 505.6g dough will over-proof.
Does converting to yeast change the fermentation time?
Dramatically. A levain dough on this 505.6g base would need many hours; the 7.1g of commercial yeast gives you a 1.5 – 2.0 hours warm bulk rise.
Why is my converted dough less extensible than the original?
Usually because the 44.4g of restored water was not added, leaving the dough drier and tighter, or because the levain's proteolysis was doing part of the gluten-softening work.