How to Replace 2g (⅔ tsp) Active Dry Yeast with Sourdough Starter in a 400g Flour Recipe
Zero-drift flour and water deduction guide for converting low-yeast (2g active dry yeast) artisan or poolish doughs into 80g sourdough levain.
Swapping 2 grams (⅔ tsp) Active Dry Yeast into sourdough on a 400g flour + 280g liquid formula yields 80g active levain at 20% baker's math (subtracting 40g flour and 40g water for 360g F / 240g W), or 22.9g by direct packet scaling (-11.4g F / -11.4g W).
- Direct Yeast Equivalent
- 22.9g StarterDeduct 11.4g flour & 11.4g water
- 20% Artisan Inoculation
- 80g StarterDeduct 40g flour & 40g water
- Adjusted Main Flour/Water
- 360g / 240gPreserves 400g total system flour at 20% levain
- Sourdough Bulk Window
- 4.0 – 5.5 hoursAt 76°F (24°C) vs. 1–1.5 hrs for commercial yeast
Hidden Flour & Water Inside the Levain (2g Active Dry Yeast → 400g dough)
Starter hydration shifts the deduction asymmetrically: a stiffer levain carries more flour and less water per gram.
| Hydration of Levain | Yeast-Equivalent Starter | Remaining Main Formula | Baker's-Math Starter | Remaining Main Formula |
|---|---|---|---|---|
| 500g flour @ 50% [Primary] | 22.9g starter (15.2g F / 7.6g W) | 484.8g F / 342.4g W | 100g starter (66.7g F / 33.3g W) | 433.3g F / 316.7g W |
| 1000g flour @ 100% Low Hydration | 22.9g starter (11.4g F / 11.4g W) | 988.6g F / 688.6g W | 200g starter (100g F / 100g W) | 900g F / 600g W |
| 400g flour @ 125% Mid Hydration | 22.9g starter (10.2g F / 12.7g W) | 389.8g F / 267.3g W | 80g starter (35.6g F / 44.4g W) | 364.4g F / 235.6g W |
| 400g flour @ 75% High Hydration | 22.9g starter (13.1g F / 9.8g W) | 386.9g F / 270.2g W | 80g starter (45.7g F / 34.3g W) | 354.3g F / 245.7g W |
| 400g flour @ 100% Standard 100% | 22.9g starter (11.4g F / 11.4g W) | 388.6g F / 268.6g W | 80g starter (40g F / 40g W) | 360g F / 240g W |
Custom Batch Recalculation Engine
Fine-tune starter hydration between 50% stiff and 125% liquid while keeping your yeast ↔ sourdough conversion ratios locked.
Replacing Low-Inoculation 2g Active Dry Yeast in 400g Flour Without Shifting Hydration
Water is the silent variable in this swap. 2g of active dry yeast brings essentially no water with it, but 22.9g of levain brings 11.4g. Add that to 280g without deducting it and the 400g dough lands well above 70% hydration and spreads.
Rye and whole wheat behave differently under conversion. Their weaker gluten absorbs the 11.4g of hidden starter water more readily, so a 400g rye formula converts with less structural penalty than a refined wheat one at the same 70% hydration.
3-Step Conversion Checklist (2g Active Dry Yeast → Sourdough in 400g Flour)
- Autolyse First: Combine 360g flour with 240g water (holding back 10% for salt) and rest 45 minutes.
- Add 80g of Ripe Levain: Pinch in the culture, add 2% salt with the reserved water, and mix until the dough is cohesive.
- Four Folds: Space two stretch and folds and two coil folds 30 minutes apart to build gluten without tearing the gas cells.
- Bulk, Shape and Retard: Reach the target rise, shape, and refrigerate 12–16 hours at 38°F before the final bake.
Technical Q&A: How to Replace 2g (⅔ tsp) Active Dry Yeast with
How much longer does sourdough take to rise than 2 g of Active Dry Yeast?
Expect bulk fermentation on a 400g flour batch to take 4.0 – 5.5 hours at 76°F (24°C), roughly 3 to 4 times longer than commercial active dry yeast.
Can I halve the recipe and still use 2g of Active Dry Yeast?
You can, but the effective inoculation doubles, so 22.9g of levain on half the flour ferments faster than the original. Plan for a shorter bulk.
How do I convert a sweet or enriched recipe with 2g of Active Dry Yeast?
The grain and water deduction is identical, but reduce the sugar by about 10%–15%, because the 4.0 – 5.5 hours at 76°F (24°C) sourdough ferment converts more of it than a two-hour commercial rise.