Convert 300g Sourdough Starter (80% Hydration) to Commercial Yeast
How to remove 300g of 80% hydration levain from any sourdough recipe by restoring +166.7g flour and +133.3g water.
Replacing 300g of 80% hydration levain with commercial yeast requires restoring +166.7g dry flour and +133.3g water so batch mass and 72.7% True Hydration stay unchanged (616.7g total flour / 448.3g total water on a 450g base), paired with 8.6g (2.8 tsp) Instant Dry Yeast.
- Add Back Flour
- +166.7gReplaces flour inside 300g (80%) starter
- Add Back Water
- +133.3gReplaces water inside 300g (80%) starter
- Instant Yeast (2-Hr Rise)
- 8.6g (2.8 tsp)For 616.7g total flour batch
- Preserved Hydration
- 72.7%448.3g W / 616.7g F
Sourdough-to-Yeast Conversion Table: 300g 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 |
|---|---|---|---|---|
| [Baseline]: 280g starter at 80% | instant 8.5g | active dry 10.6g | fresh 25.4g | bake 1.5 – 2.0 hours warm bulk rise |
| Smaller Batch: 300g starter at 80% | instant 4.3g | active dry 5.4g | fresh 13g | bake 3.5 – 4.5 hours slow room-temp rise |
| Larger Batch: 320g starter at 80% | instant 1.6g | active dry 2g | fresh 4.7g | bake 12 – 18 hours cold fermentation (39°f / 4°c) |
| Half Size: 290g starter at 80% | instant 8.6g | active dry 10.7g | fresh 25.7g | bake 1.5 – 2.0 hours warm bulk rise |
| Double Size: 310g starter at 80% | instant 4.4g | active dry 5.4g | fresh 13.1g | 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 300g of 80% Hydration Starter: Flour + Water Conservation
Converting a levain to commercial yeast also converts a flavour problem. The 6g of residual lactic and acetic acid inside 300 grams of starter contributes aroma and dough-softening that no commercial yeast can replace, so a converted dough usually benefits from a little extra fat or a riper flour.
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 (300g @ 80%)
- Audit the Original Formula: Confirm the recipe's yeast was the only leavening, and that the 300g of 80% starter was the sole source of the 166.7g of hidden flour.
- Rebuild at Full Scale: The dough is now 616.7g flour and 448.3g liquid — the same numbers as before, minus the starter.
- Dose for the Schedule You Want: 8.6g (2.8 tsp) of instant yeast for a 1.5 – 2.0 hours warm bulk rise; use about a fifth of that for a cold overnight ferment.
- Bake and Compare: The crumb will be lighter and less acid-forward, but the volume and crust colour should be close to the levain original.
Frequently Asked Questions for This Sourdough → Yeast Reverse Conversion Spec
Why is my converted dough less extensible than the original?
Usually because the 133.3g 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.
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 8.6g by the ratio of the new flour weight to 616.7g.
How much instant yeast replaces 300g of 80% sourdough starter?
For a standard 1.5–2 hour rise on a 616.7g total grain loaf, use 8.6g (2.8 tsp) of Instant Dry Yeast and add back 166.7g grain + 133.3g water.