How to Replace 3g (1 tsp) Fresh Cake Yeast with Sourdough Starter in a 500g Flour Recipe
Zero-drift flour and water deduction guide for converting low-yeast (3g fresh cake yeast) artisan or poolish doughs into 100g sourdough levain.
Converting 500g grain and 350g water from 3g Fresh Cake Yeast to 100% hydration levain requires deducting starter mass so 70% True Total Hydration holds steady: weigh 100g starter with 450g main grain and 300g liquid (20% mode) or 14.3g starter with 492.9g grain and 342.9g liquid (packet mode).
- Direct Yeast Equivalent
- 14.3g StarterDeduct 7.1g flour & 7.1g 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
Starter Deduction Grid for 3g (1 tsp) Fresh Cake Yeast in 500g Flour
Exact starter weights and main dough flour/water deductions for 3g Fresh Cake Yeast in 500g flour so True Total Hydration never drifts.
| Starter Hydration Level | Levain Required by Yeast Weight | Flour & Liquid Left in the Bowl | Levain Required at 20% Inoculation | Corrected Main Mix |
|---|---|---|---|---|
| 50% starter on 500g [Primary] | packet mode 14.3g | main 490.5g / 345.2g | 20% mode 100g | main 433.3g / 316.7g |
| 100% starter on 500g Low Hydration | packet mode 14.3g | main 492.9g / 342.9g | 20% mode 100g | main 450g / 300g |
| 125% starter on 1000g Mid Hydration | packet mode 14.3g | main 993.7g / 692.1g | 20% mode 200g | main 911.1g / 588.9g |
| 75% starter on 400g High Hydration | packet mode 14.3g | main 391.8g / 273.9g | 20% mode 80g | main 354.3g / 245.7g |
| 100% starter on 500g Standard 100% | packet mode 14.3g | main 492.9g / 342.9g | 20% mode 100g | main 450g / 300g |
Dynamic Stoichiometric Workbench (14.3g Starter)
Test custom loaf weights or alternative fermentation schedules directly against the 100g Starter benchmark above.
Replacing Low-Inoculation 3g Fresh Cake Yeast in 500g Flour Without Shifting Hydration
Salt interacts with the swap in a way that surprises people. Commercial yeast contributes no salt, while your sourdough culture was itself salted when it was last fed, so converting 3g of Fresh Cake Yeast on a 500g base usually lets you shave a fraction of a gram off the salt line without the dough losing structure.
Temperature expectations change too. Because a 500g levain dough ferments more slowly, the bulk window shifts, and bakers who keep the old 76°F target often find their 100g starter version over-proofing in a warm kitchen where the commercial version never had time to over-proof.
3-Step Conversion Checklist (3g Fresh Cake Yeast → Sourdough in 500g Flour)
- Prepare the Levain Ahead: Build 100g of ripe 100% hydration starter and feed it early enough that it domes before you mix the 500g dough.
- Mix Flour and Liquid (450g + 300g): Combine the adjusted flour and liquid, reserving 10% of the water for the salt.
- Add Starter and Salt: Work in 100g of levain plus 2% salt, then perform 4 sets of stretch and coil folds at 30-minute intervals.
- Bulk to +50% and Shape: Let the 500g batch rise to the target aliquot volume, preshape, bench rest 20 minutes, and shape before a long cold retard.
Key Baker's Math Questions (Direct Yeast Equivalent: 14.3g Starter)
What salt level should I use on the converted 500g dough?
Keep 2% of the total system flour, which on a 500g base with 50g of starter flour is about 11g of salt.
How much flour and water do I subtract when adding 100g starter to 500g flour?
At 100% starter hydration, subtract 50g flour and 50g water/milk from your 500g flour recipe (leaving 450g flour and 300g liquid).
Is a 500g sourdough conversion suitable for a pizza or focaccia base?
Yes, and long cold retarding is often an advantage for pizza. Mix 100g of levain into 450g flour and 300g water and refrigerate 24–48 hours.