How to Convert 100g Stiff Sourdough Starter (50% Hydration) to Commercial Yeast
Restoring +66.7g flour and +33.3g water when replacing 100g of 50% stiff levain with dry or fresh yeast.
Converting 100 g of 50% starter to yeast in one line: restore 66.7g of flour and 33.3g of water to the main dough, yielding 516.7g of flour and 348.3g of liquid at 67.4% true hydration, then dose 7.2g (2.3 tsp) of instant yeast for a 1.5 – 2.0 hours warm bulk rise.
- Add Back Flour
- +66.7gReplaces flour inside 100g (50%) starter
- Add Back Water
- +33.3gReplaces water inside 100g (50%) starter
- Instant Yeast (2-Hr Rise)
- 7.2g (2.3 tsp)For 516.7g total flour batch
- Preserved Hydration
- 67.4%348.3g W / 516.7g F
Sourdough-to-Yeast Conversion Table: 100g at 50% Hydration
The restoration column shows the flour and water that must go back into the main mix to keep the 67.4% hydration intact.
| Proofing Plan | Instant Dry Yeast | Active Dry Yeast | Fresh Compressed Yeast | Dough Restoration |
|---|---|---|---|---|
| Line 80g / 50% [Exact Target] | 7g IDY (2.3 tsp) | 8.8g ADY (2.8 tsp) | 21.1g cake yeast | 1.5 – 2.0 hours warm bulk rise |
| Line 100g / 50% Alt Row A | 3.6g IDY (1.2 tsp) | 4.5g ADY (1.5 tsp) | 10.9g cake yeast | 3.5 – 4.5 hours slow room-temp rise |
| Line 120g / 50% Alt Row B | 1.3g IDY (0.4 tsp) | 1.7g ADY (0.5 tsp) | 4g cake yeast | 12 – 18 hours cold fermentation (39°F / 4°C) |
| Line 90g / 50% Alt Row C | 7.1g IDY (2.3 tsp) | 8.9g ADY (2.9 tsp) | 21.4g cake yeast | 1.5 – 2.0 hours warm bulk rise |
| Line 110g / 50% Alt Row D | 3.7g IDY (1.2 tsp) | 4.6g ADY (1.5 tsp) | 11g cake yeast | 3.5 – 4.5 hours slow room-temp rise |
Real-Time Dough & Starter Scaling Sandbox
Scale this Convert 100g Stiff Sourdough Levain specification up or down on your digital scale with zero hydration drift.
Decomposing 100g of 50% Stiff Levain: High-Flour Mass Conservation
Salt interacts with the change. A levain dough was usually formulated for a 2% salt dough, and swapping in 7.2g of commercial yeast on the same 516.7g of flour keeps that salt level, which is a sensible place to leave the formula alone.
The acid-free dough behaves differently in the mixer. Commercial yeast raises gas faster, so the dough will feel more elastic earlier and needs less mechanical work; over-mixing is the most common failure in a converted batch.
Step-by-Step Reverse Conversion Protocol (100g @ 50%)
- Weigh the Restoration (66.7g + 33.3g): Set out the flour and water that were hiding inside the 100g of 50% starter before you do anything else.
- Build the Dough (516.7g F / 348.3g W): Combine them with the original 450g and 315g, then add 2% salt and 7.2g 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.
Diagnostic Answers: Convert 100g Stiff Sourdough Levain (50% Hyd
How much flour and water are inside 100g of 50% hydration starter?
100g of 50% hydration sourdough starter contains 66.7g flour and 33.3g water.
Will my converted dough taste different from the levain version?
Yes. The roughly 2g of residual acid inside 100g of levain was providing both flavour and tenderising, and commercial yeast replaces neither.
Can I scale the conversion to a different flour weight?
Yes. The yeast dose is a percentage of total flour, so on a larger batch multiply 7.2g by the ratio of the new flour weight to 516.7g.