How to Replace 2g (⅔ tsp) Fresh Cake Yeast with Sourdough Starter in a 500g Flour Recipe
Zero-drift flour and water deduction guide for converting low-yeast (2g fresh cake yeast) artisan or poolish doughs into 100g sourdough levain.
Start with the mass balance. 2 grams of fresh cake yeast contributes no flour and no water to your dough; 9.5g of 100% hydration starter contributes 4.8g of each. So a 500g flour, 350g liquid formula becomes 495.2 grams flour and 345.2 grams liquid once the levain goes in, and the dough will ferment on sourdough's clock rather than yeast's.
- Direct Yeast Equivalent
- 9.5g StarterDeduct 4.8g flour & 4.8g 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
Hidden Flour & Water Inside the Levain (2g Fresh Cake Yeast → 500g 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 @ 50% [Baseline] | 9.5g levain | subtract 6.3g flour, 3.2g water | 100g levain | subtract 66.7g flour, 33.3g water |
| Case 500g @ 100% Stiffer Starter | 9.5g levain | subtract 4.8g flour, 4.8g water | 100g levain | subtract 50g flour, 50g water |
| Case 1000g @ 125% Wetter Starter | 9.5g levain | subtract 4.2g flour, 5.3g water | 200g levain | subtract 88.9g flour, 111.1g water |
| Case 400g @ 75% Lighter Starter | 9.5g levain | subtract 5.4g flour, 4.1g water | 80g levain | subtract 45.7g flour, 34.3g water |
| Case 500g @ 100% Heavier Starter | 9.5g levain | subtract 4.8g flour, 4.8g water | 100g levain | subtract 50g flour, 50g water |
Real-Time Dough & Starter Scaling Sandbox
Scale this Convert 2g (⅔ tsp) Fresh Cake Yeast specification up or down on your digital scale with zero hydration drift.
Replacing Low-Inoculation 2g Fresh Cake Yeast in 500g Flour Without Shifting Hydration
Flour mass moves too, and bakers tend to forget it. The 4.8g of pre-fermented flour inside 9.5g of levain means the true total flour of your dough is not 500g but 504.8g once the starter is added, which is what makes 70% the correct target rather than the naive 70%.
Timing is the practical difference. A 500g dough raised with 2g of fresh cake yeast would be ready in ninety minutes, while the same dough carrying 100g of levain needs 4.0 – 5.5 hours at 76°F (24°C) and a long cold retard to develop the same flavour depth.
3-Step Conversion Checklist (2g Fresh Cake Yeast → Sourdough in 500g Flour)
- Calculate the Deduction First: 9.5g of starter carries 4.8g of flour and 4.8g of water, so write those two numbers on your bench sheet before you open the flour bag.
- Build the 500g Base: Use 495.2g flour and 345.2g liquid, which keeps the dough at 70% true hydration.
- Incorporate 9.5g 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.
Diagnostic Answers: Convert 2g (⅔ tsp) Fresh Cake Yeast to Sourd
How do I convert a sweet or enriched recipe with 2g of Fresh Cake 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.
Can I use a 50% hydration levain when converting 2g of Fresh Cake Yeast?
Yes, but the deduction changes: 9.5g at 50% hydration holds 6g flour and 3g water, so deduct those two figures instead.
Will my 500g sourdough version rise the same way as the 2g fresh cake yeast original?
No. Sourdough produces gas more slowly and with different gas retention, so judge the converted dough by +50% volumetric rise in a straight-sided jar rather than by doubling in a bowl.