Convert 50g Sourdough Starter (80% Hydration) to Commercial Yeast
How to remove 50g of 80% hydration levain from any sourdough recipe by restoring +27.8g flour and +22.2g water.
Think of the swap as a bookkeeping exercise, not a recipe change. 50g of 80% starter is not 50g of nothing — it is 27.8g of flour and 22.2g of water that you are about to delete. Put them back, and the batch returns to 477.8g flour and 337.2g water at 70.6% hydration, now leavened by 6.7g of instant yeast for a 1.5 – 2.0 hours warm bulk rise.
- Add Back Flour
- +27.8gReplaces flour inside 50g (80%) starter
- Add Back Water
- +22.2gReplaces water inside 50g (80%) starter
- Instant Yeast (2-Hr Rise)
- 6.7g (2.2 tsp)For 477.8g total flour batch
- Preserved Hydration
- 70.6%337.2g W / 477.8g F
Three Fermentation Schedules for a 50g (80%) Starter Swap
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 |
|---|---|---|---|---|
| Standard Same-Day (1.5–2 hrs) — 70g (80%) [Exact Target] | IDY 6.8g / 2.2 tsp | ADY 8.6g / 2.8 tsp | fresh 20.5g | restore 38.9g + 31.1g |
| Slow Artisan Bulk (3.5–4.5 hrs) — 50g (80%) Alt Row A | IDY 3.3g / 1.1 tsp | ADY 4.2g / 1.3 tsp | fresh 10g | restore 27.8g + 22.2g |
| Overnight No-Knead / Cold Proof (12–18 hrs) — 30g (80%) Alt Row B | IDY 1.2g / 0.4 tsp | ADY 1.5g / 0.5 tsp | fresh 3.5g | restore 16.7g + 13.3g |
| Standard Same-Day (1.5–2 hrs) — 60g (80%) Alt Row C | IDY 6.8g / 2.2 tsp | ADY 8.5g / 2.7 tsp | fresh 20.3g | restore 33.3g + 26.7g |
| Slow Artisan Bulk (3.5–4.5 hrs) — 40g (80%) Alt Row D | IDY 3.3g / 1.1 tsp | ADY 4.1g / 1.3 tsp | fresh 9.9g | restore 22.2g + 17.8g |
Dynamic Stoichiometric Workbench (+27.8g)
Test custom loaf weights or alternative fermentation schedules directly against the +22.2g benchmark above.
Decomposing 50g of 80% Hydration Starter: Flour + Water Conservation
By definition, a starter hydrated at 80% contains 100 parts grain and 80 parts water. Using Flour = 50 ÷ (1 + 0.8), your 50g of starter holds 27.8g of grain and 22.2g of water.
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 (50g @ 80%)
- Restore Base Ingredients (+27.8g F / +22.2g W): Add 27.8g grain and 22.2g water to your main dough (477.8g F / 337.2g W).
- Select Yeast Inoculation by Schedule: Weigh 6.7g (2.2 tsp) Instant Yeast for a 90–120 min rise, or scale down for a 4-hour artisan bulk.
- Mix & Proof Directly: Combine all 477.8g grain, 337.2g water, yeast, and salt without a pre-ferment build.
- Bake on Schedule: Shape once, proof for the remaining time, and bake the moment the dough has doubled rather than waiting for the slow souring a levain would deliver.
Key Baker's Math Questions (Add Back Flour: +27.8g)
Does converting to yeast change the fermentation time?
Dramatically. A levain dough on this 477.8g base would need many hours; the 6.7g of commercial yeast gives you a 1.5 – 2.0 hours warm bulk rise.
How much flour and water are inside 50g of 80% hydration starter?
50g of 80% hydration sourdough starter contains 27.8g flour and 22.2g water.
Can I use Active Dry Yeast instead of Instant Yeast to replace 50g starter?
Yes — multiply the 6.7g Instant Yeast weight by 1.25x and dissolve it in warm (100°F / 38°C) water from your 22.2g water addition.