How to Replace 2g (⅔ tsp) Instant Dry Yeast with Sourdough Starter in a 1000g Flour Recipe
Zero-drift flour and water deduction guide for converting low-yeast (2g instant dry yeast) artisan or poolish doughs into 200g sourdough levain.
Swapping 2g (⅔ tsp) Instant Dry Yeast into sourdough on a 1000g flour + 700g liquid formula yields 200g active levain at 20% baker's math (subtracting 100g flour and 100g water for 900g F / 600g W), or 28.6g by direct packet scaling (-14.3g F / -14.3g W).
- Direct Yeast Equivalent
- 28.6g StarterDeduct 14.3g flour & 14.3g 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
Starter Deduction Grid for 2g (⅔ tsp) Instant Dry Yeast in 1000g Flour
Compare the packet-equivalency column against the 20% baker's math column to see how much the two conventions diverge on a 1000g base.
| Starter Hydration Level | Levain Required by Yeast Weight | Flour & Liquid Left in the Bowl | Levain Required at 20% Inoculation | Corrected Main Mix |
|---|---|---|---|---|
| 100% starter on 1000g [Anchor] | packet mode 28.6g | main 985.7g / 685.7g | 20% mode 200g | main 900g / 600g |
| 125% starter on 500g One Step Down | packet mode 28.6g | main 487.3g / 334.1g | 20% mode 100g | main 455.6g / 294.4g |
| 50% starter on 1000g One Step Up | packet mode 28.6g | main 981g / 690.5g | 20% mode 200g | main 866.7g / 633.3g |
| 100% starter on 400g Two Steps Down | packet mode 28.6g | main 385.7g / 265.7g | 20% mode 80g | main 360g / 240g |
| 75% starter on 1000g Two Steps Up | packet mode 28.6g | main 983.7g / 687.8g | 20% mode 200g | main 885.7g / 614.3g |
Real-Time Dough & Starter Scaling Sandbox
Scale this Convert 2g (⅔ tsp) Instant Dry Yeast specification up or down on your digital scale with zero hydration drift.
Replacing Low-Inoculation 2g Instant Dry Yeast in 1000g Flour Without Shifting Hydration
Commercial instant dry yeast (2 g) introduces negligible moisture to a 1000g flour mix, whereas 200g of 100% hydration levain carries 100g fermented flour and 100g water. Deducting those exact weights keeps the 1000g system at 70% hydration.
Direct packet scaling of 2 g (⅔ tsp) Instant Dry Yeast maps to 28.6g starter (-14.3g flour / -14.3g 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 (2g Instant Dry Yeast → Sourdough in 1000g Flour)
- Calculate the Deduction First: 28.6g of starter carries 14.3g of flour and 14.3g of water, so write those two numbers on your bench sheet before you open the flour bag.
- Build the 1000g Base: Use 985.7g flour and 685.7g liquid, which keeps the dough at 70% true hydration.
- Incorporate 28.6g of Starter: Dimple in the sourdough culture and 2% salt, mix to full cohesion, and rest 30 minutes before the first fold.
- Watch the Aliquot, Not the Clock: Ferment at 75°F until a 30g sample reaches +50% volume, which on sourdough is far more reliable than a timer.
Diagnostic Answers: Convert 2g (⅔ tsp) Instant Dry Yeast to Sour
Does the type of commercial yeast change the starter weight?
Yes. Instant Dry Yeast has its own potency per gram, so 2g of it converts to 28.6g of levain rather than the 200g that the 20% rule would prescribe on a 1000g base.
Why does my converted 1000g dough feel stickier than the original?
Almost always the 14.3g of hidden starter water was not deducted. Correct the liquid to 685.7g and the dough will tighten immediately.
Can I convert a 1000g dough that already contains a preferment or poolish?
Yes, but dissolve the preferment's yeast into the main mix first so the full 2g of leavening power is counted. Then deduct 14.3g flour and 14.3g water for the levain you are adding.