How to Replace 2g (⅔ tsp) Fresh Cake Yeast with Sourdough Starter in a 1000g Flour Recipe
Zero-drift flour and water deduction guide for converting low-yeast (2g fresh cake yeast) artisan or poolish doughs into 200g sourdough levain.
Swapping 2g (⅔ tsp) Fresh Cake 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 9.5g by direct packet scaling (-4.8g F / -4.8g W).
- Direct Yeast Equivalent
- 9.5g StarterDeduct 4.8g flour & 4.8g 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
Replacing 2g Fresh Cake Yeast in 1000g Flour Across 50% to 125% Starter Hydrations
Compare the packet-equivalency column against the 20% baker's math column to see how much the two conventions diverge on a 1000g base.
| Levain Hydration % | Packet Mode Starter & Deductions | Packet Mode Main Mix | 20% Mode Starter & Deductions | 20% Mode Main Mix |
|---|---|---|---|---|
| Case 500g @ 125% [Anchor] | 9.5g levain | subtract 4.2g flour, 5.3g water | 100g levain | subtract 44.4g flour, 55.6g water |
| Case 1000g @ 75% One Step Down | 9.5g levain | subtract 5.4g flour, 4.1g water | 200g levain | subtract 114.3g flour, 85.7g water |
| Case 400g @ 100% One Step Up | 9.5g levain | subtract 4.8g flour, 4.8g water | 80g levain | subtract 40g flour, 40g water |
| Case 1000g @ 100% Two Steps Down | 9.5g levain | subtract 4.8g flour, 4.8g water | 200g levain | subtract 100g flour, 100g water |
| Case 1000g @ 50% Two Steps Up | 9.5g levain | subtract 6.3g flour, 3.2g water | 200g levain | subtract 133.3g flour, 66.7g 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 1000g Flour Without Shifting Hydration
Because fresh cake yeast is a pure monoculture of Saccharomyces cerevisiae, transitioning your 1000g batch to sourdough requires tracking volumetric aliquot rise (+50%) over 4.0 – 5.5 hours at 76°F (24°C) rather than watching a 60-minute clock.
Rye and whole wheat behave differently under conversion. Their weaker gluten absorbs the 4.8g of hidden culture water more readily, so a 1000g rye formula converts with less structural penalty than a refined wheat one at the same 70% hydration.
3-Step Conversion Checklist (2g Fresh Cake 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.
Diagnostic Answers: Convert 2g (⅔ tsp) Fresh Cake Yeast to Sourd
Can I use a 50% hydration sourdough culture 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.
Does converting to sourdough change the dough weight?
Yes, slightly. The 1000g grain and 700g liquid original carried 2g of dry yeast; the levain version carries 9.5g of starter instead, so expect a small shift in finished loaf weight.
How much flour and water do I subtract when adding 200g starter to 1000g flour?
At 100% starter hydration, subtract 100g flour and 100g water/milk from your 1000g flour recipe (leaving 900g flour and 600g liquid).