Convert 5g (1⅔ tsp) Fresh Cake Yeast to Sourdough Starter (400g Flour Recipe)
Zero-drift flour and liquid deduction math for converting 5g of fresh cake yeast into 50%–125% hydration sourdough levain on a 400g base.
If your goal is simply a sourdough version of a 400g formula that used 5g of Fresh Cake Yeast, the simplest path is 20% inoculation: 80g of ripe levain, with 40g flour and 40g water removed from the main mix, leaving 360g and 240g. Expect 4.0 – 5.5 hours at 76°F (24°C) instead of a two-hour rise.
- Direct Yeast Equivalent
- 23.8g StarterDeduct 11.9g flour & 11.9g water
- 20% Artisan Inoculation
- 80g StarterDeduct 40g flour & 40g water
- Adjusted Main Flour/Water
- 360g / 240gPreserves 400g 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
Yeast-to-Sourdough Conversion Table: 5g Fresh Cake Yeast on a 400g Base
Starter hydration shifts the deduction asymmetrically: a stiffer levain carries more flour and less water per gram.
| Starter Hydration | Packet-Equivalent Starter (Deductions) | Adjusted Main Dough (Packet Mode) | 20% Artisan Starter (Deductions) | Adjusted Main Dough (20% Mode) |
|---|---|---|---|---|
| [Primary]: 1000g / 100% | hidden 11.9g F + 11.9g W | → 988.1g / 688.1g | hidden 100g F + 100g W | → 900g / 600g |
| Low Hydration: 400g / 125% | hidden 10.6g F + 13.2g W | → 389.4g / 266.8g | hidden 35.6g F + 44.4g W | → 364.4g / 235.6g |
| Mid Hydration: 400g / 50% | hidden 15.9g F + 7.9g W | → 384.1g / 272.1g | hidden 53.3g F + 26.7g W | → 346.7g / 253.3g |
| High Hydration: 500g / 100% | hidden 11.9g F + 11.9g W | → 488.1g / 338.1g | hidden 50g F + 50g W | → 450g / 300g |
| Standard 100%: 400g / 75% | hidden 13.6g F + 10.2g W | → 386.4g / 269.8g | hidden 45.7g F + 34.3g W | → 354.3g / 245.7g |
Custom Batch Recalculation Engine
Fine-tune starter hydration between 50% stiff and 125% liquid while keeping your yeast ↔ sourdough conversion ratios locked.
Why 5g Fresh Cake Yeast Cannot Be Swapped in 400g Flour Without Deducting Starter Water
Salt interacts with the swap in a way that surprises people. Commercial yeast contributes no salt, while your levain was itself salted when it was last fed, so converting 5 g of Fresh Cake Yeast on a 400g base usually lets you shave a fraction of a gram off the salt line without the dough losing structure.
Proofing structure matters more once you cross over. A levain at 100% hydration is a paste rather than a liquid, so it disperses differently through the 400g of grain than the measured 280g of water it replaces, and the dough usually needs an extra set of folds in the first hour.
3-Step Conversion Checklist (5g Fresh Cake Yeast → Sourdough in 400g Flour)
- Calculate the Deduction First: 23.8g of starter carries 11.9g of flour and 11.9g of water, so write those two numbers on your bench sheet before you open the flour bag.
- Build the 400g Base: Use 388.1g flour and 268.1g liquid, which keeps the dough at 70% true hydration.
- Incorporate 23.8g 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.
Technical Q&A: Convert 5g (1⅔ tsp) Fresh Cake Yeast to Sourdoug
Will my 400g sourdough version rise the same way as the 5 grams 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.
How do I convert a sweet or enriched recipe with 5g 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.
Should I use 23.8g or 80g of starter?
Use 23.8g if you want to preserve the exact leavening power of 5g fresh cake yeast. Use 80g if you want standard 20% artisan inoculation regardless of the original yeast weight.