How to Convert 60g Stiff Sourdough Starter (50% Hydration) to Commercial Yeast
Restoring +40g flour and +20g water when replacing 60g of 50% stiff levain with dry or fresh yeast.
Converting 60g of 50% levain to yeast in one line: restore 40g of flour and 20g of water to the main dough, yielding 490g of flour and 335g of liquid at 68.4% true hydration, then dose 6.9g (2.2 tsp) of instant yeast for a 1.5 – 2.0 hours warm bulk rise.
- Add Back Flour
- +40gReplaces flour inside 60g (50%) starter
- Add Back Water
- +20gReplaces water inside 60g (50%) starter
- Instant Yeast (2-Hr Rise)
- 6.9g (2.2 tsp)For 490g total flour batch
- Preserved Hydration
- 68.4%335g W / 490g F
Gram Weights for Replacing 60g of 50% Hydration Starter
Calculated on a 450g main flour + 40g restored starter flour (490g total flour) batch.
| Target Fermentation Schedule | Instant Dry Yeast (IDY) | Active Dry Yeast (ADY) | Fresh Compressed Yeast | Required Dough Restoration |
|---|---|---|---|---|
| Standard Same-Day (1.5–2 hrs) — 60g (50%) [Exact Target] | IDY 6.9g / 2.2 tsp | ADY 8.6g / 2.8 tsp | fresh 20.6g | restore 40g + 20g |
| Slow Artisan Bulk (3.5–4.5 hrs) — 70g (50%) Alt Row A | IDY 3.5g / 1.1 tsp | ADY 4.3g / 1.4 tsp | fresh 10.4g | restore 46.7g + 23.3g |
| Overnight No-Knead / Cold Proof (12–18 hrs) — 50g (50%) Alt Row B | IDY 1.2g / 0.4 tsp | ADY 1.5g / 0.5 tsp | fresh 3.6g | restore 33.3g + 16.7g |
| Standard Same-Day (1.5–2 hrs) — 80g (50%) Alt Row C | IDY 7g / 2.3 tsp | ADY 8.8g / 2.8 tsp | fresh 21.1g | restore 53.3g + 26.7g |
| Slow Artisan Bulk (3.5–4.5 hrs) — 40g (50%) Alt Row D | IDY 3.3g / 1.1 tsp | ADY 4.2g / 1.3 tsp | fresh 10g | restore 26.7g + 13.3g |
Dynamic Stoichiometric Workbench (+40g)
Test custom loaf weights or alternative fermentation schedules directly against the +20g benchmark above.
Decomposing 60g of 50% Stiff Levain: High-Flour Mass Conservation
Yeast dose scales with total flour, not with the amount of starter you removed. On a 450g base that becomes 490g of system flour, the 1.4% instant-yeast rule for a two-hour rise lands on 6.9g, and every hour you extend the schedule cuts that figure.
Shelf life shortens. The 68.4% hydration dough leavened by 6.9g of yeast stales faster than the levain version, because there is no residual acid to slow starch retrogradation.
Step-by-Step Reverse Conversion Protocol (60g @ 50%)
- Weigh the Restoration (40g + 20g): Set out the flour and water that were hiding inside the 60g of 50% starter before you do anything else.
- Build the Dough (490g F / 335g W): Combine them with the original 450g and 315g, then add 2% salt and 6.9g of instant yeast.
- Mix and Rest: Knead to a smooth, cohesive batch 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.
Key Baker's Math Questions (Add Back Flour: +40g)
Will my converted dough taste different from the levain version?
Yes. The roughly 1g of residual acid inside 60g of starter was providing both flavour and tenderising, and commercial yeast replaces neither.
How much instant yeast replaces 60g of 50% sourdough starter?
For a standard 1.5–2 hour rise on a 490g total flour loaf, use 6.9g (2.2 tsp) of Instant Dry Yeast and add back 40g flour + 20g water.
Is 60g of 50% starter easier to replace than a wetter starter?
Easier in one sense: a stiffer starter carries more flour and less water per gram, so the 40g / 20g restoration is larger on the flour side and smaller on the water side.