Convert 7g (1 Packet / 2¼ tsp) Active Dry Yeast to Sourdough Starter (500g Flour Recipe)
Zero-drift flour and liquid deduction math for converting 7g of active dry yeast into 50%–125% hydration sourdough levain on a 500g base.
Swapping 7g (1 Packet / 2¼ tsp) Active Dry Yeast into sourdough on a 500g flour + 350g liquid formula yields 100g active levain at 20% baker's math (subtracting 50g flour and 50g water for 450g F / 300g W), or 80g by direct packet scaling (-40g F / -40g W).
- Direct Yeast Equivalent
- 80g StarterDeduct 40g flour & 40g water
- 20% Artisan Inoculation
- 100g StarterDeduct 50g flour & 50g water
- Adjusted Main Flour/Water
- 450g / 300gPreserves 500g 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
Two Ways to Convert 7g Active Dry Yeast: Packet Equivalency vs 20% Inoculation
Use the 100% hydration row as your working formula unless your levain is deliberately stiff or liquid.
| Levain Hydration | Direct Yeast Match (Deductions) | Adjusted Dough (Direct Match) | Standard 20% Levain (Deductions) | Adjusted Dough (Standard Match) |
|---|---|---|---|---|
| Line 500g at 100% [Your Formula] | packet 80g (deduct 40g/40g) | remaining 460g + 310g | artisan 100g (deduct 50g/50g) | remaining 450g + 300g |
| Line 400g at 125% Leaner Dough | packet 80g (deduct 35.6g/44.4g) | remaining 364.4g + 235.6g | artisan 80g (deduct 35.6g/44.4g) | remaining 364.4g + 235.6g |
| Line 500g at 50% Wetter Dough | packet 80g (deduct 53.3g/26.7g) | remaining 446.7g + 323.3g | artisan 100g (deduct 66.7g/33.3g) | remaining 433.3g + 316.7g |
| Line 1000g at 100% Tighter Dough | packet 80g (deduct 40g/40g) | remaining 960g + 660g | artisan 200g (deduct 100g/100g) | remaining 900g + 600g |
| Line 500g at 75% Looser Dough | packet 80g (deduct 45.7g/34.3g) | remaining 454.3g + 315.7g | artisan 100g (deduct 57.1g/42.9g) | remaining 442.9g + 307.1g |
Custom Batch Recalculation Engine
Fine-tune starter hydration between 50% stiff and 125% liquid while keeping your yeast ↔ sourdough conversion ratios locked.
Why 7g Active Dry Yeast Cannot Be Swapped in 500g Flour Without Deducting Starter Water
Scaling the conversion is linear in the flour but not in the commercial yeast. Doubling a 500g base to 1000g while keeping 7g of Active Dry Yeast halves the effective inoculation, so 80g of levain is a far gentler ferment than 160g would be.
Judge the conversion on the dough, not on the scale. The dough should feel the same slackness it had with the original 7g of active dry yeast, dome predictably, and hold its shape at shaping. If it is spreading, the 40g of hidden starter water was not deducted.
3-Step Conversion Checklist (7g Active Dry Yeast → Sourdough in 500g Flour)
- Calculate the Deduction First: 80g of starter carries 40g of grain and 40g of water, so write those two numbers on your bench sheet before you open the grain bag.
- Build the 500g Base: Use 460g grain and 310g liquid, which keeps the dough at 70% true hydration.
- Incorporate 80g of Starter: Dimple in the levain 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.
Technical Q&A: Convert 7g (1 Packet / 2¼ tsp) Active Dry Yeast
How much sourdough starter replaces 7g of Active Dry Yeast in 500g flour?
By direct yeast weight equivalency, 7g of Active Dry Yeast equals 80g of 100% hydration sourdough starter. For a 500g flour batch, the 20% baker's inoculation is 100g starter.
Should I use 80g or 100g of starter?
Use 80g if you want to preserve the exact leavening power of 7g active dry yeast. Use 100g if you want standard 20% artisan inoculation regardless of the original yeast weight.
Does the type of commercial yeast change the starter weight?
Yes. Active Dry Yeast has its own potency per gram, so 7 g of it converts to 80g of levain rather than the 100g that the 20% rule would prescribe on a 500g base.