How to Replace 4g (1⅓ tsp) Active Dry Yeast with Sourdough Starter in a 400g Flour Recipe
Zero-drift flour and water deduction guide for converting low-yeast (4g active dry yeast) artisan or poolish doughs into 80g sourdough levain.
To replace 4g of Active Dry Yeast in a 400g flour recipe (at 70% hydration / 280g liquid), use either: (1) Direct yeast equivalency (45.7g of 100% starter, deducting 22.9g flour and 22.9g liquid to leave 377.1g flour and 257.1g water); or (2) Standard 20% artisan inoculation (80g starter, leaving 360g flour and 240g water at 70% True Hydration).
- Direct Yeast Equivalent
- 45.7g StarterDeduct 22.9g flour & 22.9g 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 (4g Active Dry Yeast → 400g dough)
Rows recompute the full conversion independently, so the flour, liquid and starter columns always reconcile.
| Hydration of Levain | Yeast-Equivalent Starter | Remaining Main Formula | Baker's-Math Starter | Remaining Main Formula |
|---|---|---|---|---|
| Case 500g @ 100% [Anchor] | 45.7g levain | subtract 22.9g flour, 22.9g water | 100g levain | subtract 50g flour, 50g water |
| Case 1000g @ 50% One Step Down | 45.7g levain | subtract 30.5g flour, 15.2g water | 200g levain | subtract 133.3g flour, 66.7g water |
| Case 400g @ 75% One Step Up | 45.7g levain | subtract 26.1g flour, 19.6g water | 80g levain | subtract 45.7g flour, 34.3g water |
| Case 400g @ 125% Two Steps Down | 45.7g levain | subtract 20.3g flour, 25.4g water | 80g levain | subtract 35.6g flour, 44.4g water |
| Case 400g @ 100% Two Steps Up | 45.7g levain | subtract 22.9g flour, 22.9g water | 80g levain | subtract 40g flour, 40g water |
Live Parameter Solver for How to Replace 4g (1⅓ tsp) Active Dry Yeas
Dial in custom baker's percentages and export your adjusted 45.7g Starter formula for bake day.
Replacing Low-Inoculation 4g Active Dry Yeast in 400g Flour Without Shifting Hydration
Inoculation rate, not commercial yeast weight, sets the fermentation clock. Converting 4g of active dry commercial yeast by packet equivalency on a 400g base yields an effective inoculation of 11.4%, which is why the bulk window can stretch well past the 4.0 – 5.5 hours at 76°F (24°C) quoted for standard 20% inoculation.
Keep a log. The most useful column is not the starter weight but the total elapsed time from mixing to shaping, because on the second and third bake the 400g formula with 45.7g of levain is a different dough to the one you remember.
3-Step Conversion Checklist (4g Active Dry Yeast → Sourdough in 400g Flour)
- Prepare the Levain Ahead: Build 80g of ripe 100% hydration starter and feed it early enough that it domes before you mix the 400g dough.
- Mix Flour and Liquid (360g + 240g): Combine the adjusted flour and liquid, reserving 10% of the water for the salt.
- Add Starter and Salt: Work in 80g of levain plus 2% salt, then perform 4 sets of stretch and coil folds at 30-minute intervals.
- Bulk to +50% and Shape: Let the 400g batch rise to the target aliquot volume, preshape, bench rest 20 minutes, and shape before a long cold retard.
Cereal Chemistry & Bench Execution FAQs
Can I halve the recipe and still use 4g of Active Dry Yeast?
You can, but the effective inoculation doubles, so 45.7g of levain on half the flour ferments faster than the original. Plan for a shorter bulk.
Why does my converted 400g dough feel stickier than the original?
Almost always the 22.9g of hidden starter water was not deducted. Correct the liquid to 257.1g and the dough will tighten immediately.
Can I use a 50% hydration levain when converting 4g of Active Dry Yeast?
Yes, but the deduction changes: 45.7g at 50% hydration holds 30g flour and 15g water, so deduct those two figures instead.