Convert 200g Sourdough Starter (100% Hydration) to Commercial Yeast
How to remove 200g of 100% hydration levain from any sourdough recipe by restoring +100g flour and +100g water.
The arithmetic runs in reverse. A starter at 100% hydration divides into 200 ÷ (1 + 1) of flour and the remainder as water — here 100g and 100g. Add both back to the 450g + 315g base and the dough is whole again at 550g / 415g, ready for 7.7g of commercial yeast instead of a levain.
- Add Back Flour
- +100gReplaces flour inside 200g (100%) starter
- Add Back Water
- +100gReplaces water inside 200g (100%) starter
- Instant Yeast (2-Hr Rise)
- 7.7g (2.5 tsp)For 550g total flour batch
- Preserved Hydration
- 75.5%415g W / 550g F
Yeast Replacement Matrix for 200g Starter (100% Hydration) Across 3 Fermentation Speeds
Calculated on a 450g main flour + 100g restored starter flour (550g total flour) batch.
| Target Fermentation Schedule | Instant Dry Yeast (IDY) | Active Dry Yeast (ADY) | Fresh Compressed Yeast | Required Dough Restoration |
|---|---|---|---|---|
| [Baseline]: 200g starter at 100% | instant 7.7g | active dry 9.6g | fresh 23.1g | bake 1.5 – 2.0 hours warm bulk rise |
| Smaller Batch: 190g starter at 100% | instant 3.8g | active dry 4.8g | fresh 11.4g | bake 3.5 – 4.5 hours slow room-temp rise |
| Larger Batch: 210g starter at 100% | instant 1.4g | active dry 1.7g | fresh 4.2g | bake 12 – 18 hours cold fermentation (39°f / 4°c) |
| Half Size: 180g starter at 100% | instant 7.6g | active dry 9.5g | fresh 22.7g | bake 1.5 – 2.0 hours warm bulk rise |
| Double Size: 220g starter at 100% | instant 3.9g | active dry 4.9g | fresh 11.8g | bake 3.5 – 4.5 hours slow room-temp rise |
On-Bench Hydration & Fermentation Adjuster
Modify base flour mass, levain inoculation, or ambient kitchen temperature below to recalculate from this +100g baseline.
Decomposing 200g of 100% Hydration Starter: Flour + Water Conservation
The three yeast formats are not interchangeable at equal weight. Active Dry Yeast is a live but partly dehydrated culture carrying roughly 80% of the potency per gram of IDY, while fresh compressed cake yeast is only about a third, so 7.7g of instant corresponds to 9.6g of active dry and 23.1g of fresh.
Watch the oven spring rather than the mixing. With 7.7g of commercial yeast the loaf will rise fast in the first 90 minutes, which means less time to develop a rounded shape and more chance of a flat crown if you shape too early.
Step-by-Step Reverse Conversion Protocol (200g @ 100%)
- Plan Around the Lost Complexity: Without a levain you lose the slow acid build, so if the 200g of 100% starter was there for flavour, add a little honey or malt and a spoonful of yoghurt.
- Restore the Mass: Return 100g of flour and 100g of water to the base formula.
- Dose the Yeast: 7.7g (2.5 tsp) of instant, 9.6g of active dry, or 23.1g of fresh cake yeast.
- Ferment, Shape, Bake: Respect the 1.5 – 2.0 hours warm bulk rise schedule, and remember the 75.5% hydration is unchanged by the swap.
Common Scaling & Troubleshooting Questions (+100g)
Is 200 g of 100% 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 100g / 100g restoration is larger on the flour side and smaller on the water side.
How much flour and water are inside 200 g of 100% hydration starter?
200 g of 100% hydration sourdough starter contains 100g flour and 100g water.
Can I convert a stiff 50% levain to yeast?
Yes, and the deduction is larger on the grain side: 200g at 50% hydration holds 133g grain and 67g water rather than the 100g / 100g of a 100% starter.