How to Replace 4g (1⅓ tsp) Active Dry Yeast with Sourdough Starter in a 1000g Flour Recipe
Zero-drift flour and water deduction guide for converting low-yeast (4g active dry yeast) artisan or poolish doughs into 200g sourdough levain.
There are two defensible answers to this conversion, and the difference matters. Packet-equivalency treats 4g of Active Dry Yeast as a fixed quantity of leavening power, so you need 45.7g of ripe starter and must remove 22.9g flour plus 22.9g water from the 1000g base. Baker's math instead standardises on 20% inoculation, giving 200g of starter on the same 1000g flour with 900g flour and 600g liquid left in the bowl.
- Direct Yeast Equivalent
- 45.7g StarterDeduct 22.9g flour & 22.9g water
- 20% Artisan Inoculation
- 200g StarterDeduct 100g flour & 100g water
- Adjusted Main Flour/Water
- 900g / 600gPreserves 1000g 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
Yeast-to-Sourdough Conversion Table: 4g Active Dry Yeast on a 1000g Base
Starter hydration shifts the deduction asymmetrically: a stiffer levain carries more flour and less water per gram.
| Starter Hydration | Packet-Equivalent Starter (Deductions) | Adjusted Main Dough (Packet Mode) | 20% Artisan Starter (Deductions) | Adjusted Main Dough (20% Mode) |
|---|---|---|---|---|
| 100% starter on 1000g [Anchor] | packet mode 45.7g | main 977.1g / 677.1g | 20% mode 200g | main 900g / 600g |
| 50% starter on 400g One Step Down | packet mode 45.7g | main 369.5g / 264.8g | 20% mode 80g | main 346.7g / 253.3g |
| 75% starter on 1000g One Step Up | packet mode 45.7g | main 973.9g / 680.4g | 20% mode 200g | main 885.7g / 614.3g |
| 125% starter on 500g Two Steps Down | packet mode 45.7g | main 479.7g / 324.6g | 20% mode 100g | main 455.6g / 294.4g |
| 100% starter on 1000g Two Steps Up | packet mode 45.7g | main 977.1g / 677.1g | 20% mode 200g | main 900g / 600g |
Dynamic Stoichiometric Workbench (45.7g Starter)
Test custom loaf weights or alternative fermentation schedules directly against the 200g Starter benchmark above.
Replacing Low-Inoculation 4g Active Dry Yeast in 1000g Flour Without Shifting Hydration
Salt interacts with the swap in a way that surprises people. Commercial commercial yeast contributes no salt, while your levain was itself salted when it was last fed, so converting 4g of Active Dry Yeast on a 1000g base usually lets you shave a fraction of a gram off the salt line without the dough losing structure.
Direct packet scaling of 4g (1⅓ tsp) Active Dry Yeast maps to 45.7g starter (-22.9g flour / -22.9g water), while artisan baker's math standardises inoculation at 20% of 1000g (200g starter, leaving 900g main flour and 600g liquid).
3-Step Conversion Checklist (4g Active Dry Yeast → Sourdough in 1000g Flour)
- Check the Starter Is Ripe: 200g of levain must be domed, bubbly and at full stretch; a flat starter slows the 4.0 – 5.5 hours at 76°F (24°C) window significantly.
- Combine 1000g of Flour with the Adjusted Liquid: Pour 600g, saving 10% to dissolve the salt later.
- Fold in 200g Starter and 2% Salt: Add the levain, pinch through the dough, and work in the salt water.
- Ferment to +50%: Judge by volume in a straight-sided jar, then shape, retard overnight and bake on a preheated stone or in a Dutch oven.
Key Baker's Math Questions (Direct Yeast Equivalent: 45.7g Starter)
Is a 1000g sourdough conversion suitable for a pizza or focaccia base?
Yes, and long cold retarding is often an advantage for pizza. Mix 200g of levain into 900g flour and 600g water and refrigerate 24–48 hours.
Does the type of commercial yeast change the culture weight?
Yes. Active Dry Yeast has its own potency per gram, so 4g of it converts to 45.7g of levain rather than the 200g that the 20% rule would prescribe on a 1000g base.
How do I convert a sweet or enriched recipe with 4g of Active Dry Yeast?
The flour 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.