How to Replace 3g (1 tsp) Fresh Cake Yeast with Sourdough Starter in a 1000g Flour Recipe
Zero-drift flour and water deduction guide for converting low-yeast (3g fresh cake yeast) artisan or poolish doughs into 200g sourdough levain.
Converting 1000g flour and 700g water from 3g Fresh Cake Yeast to 100% hydration sourdough culture requires deducting starter mass so 70% True Total Hydration holds steady: weigh 200g starter with 900g main flour and 600g liquid (20% mode) or 14.3g starter with 992.9g flour and 692.9g liquid (packet mode).
- Direct Yeast Equivalent
- 14.3g StarterDeduct 7.1g flour & 7.1g 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
Two Ways to Convert 3g Fresh Cake Yeast: Packet Equivalency vs 20% Inoculation
Rows recompute the full conversion independently, so the flour, liquid and starter columns always reconcile.
| Levain Hydration | Direct Yeast Match (Deductions) | Adjusted Dough (Direct Match) | Standard 20% Levain (Deductions) | Adjusted Dough (Standard Match) |
|---|---|---|---|---|
| Line 1000g at 50% [Primary] | packet 14.3g (deduct 9.5g/4.8g) | remaining 990.5g + 695.2g | artisan 200g (deduct 133.3g/66.7g) | remaining 866.7g + 633.3g |
| Line 500g at 100% Low Hydration | packet 14.3g (deduct 7.1g/7.1g) | remaining 492.9g + 342.9g | artisan 100g (deduct 50g/50g) | remaining 450g + 300g |
| Line 1000g at 125% Mid Hydration | packet 14.3g (deduct 6.3g/7.9g) | remaining 993.7g + 692.1g | artisan 200g (deduct 88.9g/111.1g) | remaining 911.1g + 588.9g |
| Line 400g at 75% High Hydration | packet 14.3g (deduct 8.2g/6.1g) | remaining 391.8g + 273.9g | artisan 80g (deduct 45.7g/34.3g) | remaining 354.3g + 245.7g |
| Line 1000g at 100% Standard 100% | packet 14.3g (deduct 7.1g/7.1g) | remaining 992.9g + 692.9g | artisan 200g (deduct 100g/100g) | remaining 900g + 600g |
On-Bench Hydration & Fermentation Adjuster
Modify base flour mass, levain inoculation, or ambient kitchen temperature below to recalculate from this 14.3g Starter baseline.
Replacing Low-Inoculation 3g Fresh Cake Yeast in 1000g Flour Without Shifting Hydration
Scaling the conversion is linear in the flour but not in the yeast. Doubling a 1000g base to 2000g while keeping 3g of Fresh Cake Yeast halves the effective inoculation, so 14.3g of levain is a far gentler ferment than 28.6g would be.
Direct packet scaling of 3 g (1 tsp) Fresh Cake Yeast maps to 14.3 g starter (-7.1g flour / -7.1g 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 (3g Fresh Cake Yeast → Sourdough in 1000g Flour)
- Weigh Active Levain (200g or 14.3 g): Measure 200g peaked 100% starter for 20% inoculation, or 14.3 g for direct 3 g Fresh Cake Yeast equivalency.
- Deduct Main Flour & Liquid (1000g Base): Scale main flour to 900g (-100g) and liquid to 600g (-100g).
- Ferment for 4.0 – 5.5 hours at 76°F (24°C): Hold the 1000g dough at 75°F–78°F until +50% volumetric expansion before shaping and cold proofing.
- Retard and Bake: Cold-proof the shaped dough for 12–16 hours at 38°F, then bake covered and uncover to a deep mahogany crust.
Common Scaling & Troubleshooting Questions (14.3g Starter)
What happens to my hydration when I swap 3g fresh cake commercial yeast for levain?
Nothing, if you deduct correctly. 14.3g of levain carries 7.1g flour and 7.1g water, so removing both keeps the 1000g dough at 70% true hydration.
Does converting to sourdough change the dough weight?
Yes, slightly. The 1000g flour and 700g liquid original carried 3g of dry yeast; the sourdough culture version carries 14.3g of starter instead, so expect a small shift in finished loaf weight.
Does the type of commercial yeast change the starter weight?
Yes. Fresh Cake Yeast has its own potency per gram, so 3g of it converts to 14.3g of levain rather than the 200g that the 20% rule would prescribe on a 1000g base.