Convert 6g (2 tsp) Fresh Cake Yeast to Sourdough Starter (400g Flour Recipe)
Zero-drift flour and liquid deduction math for converting 6g of fresh cake yeast into 50%–125% hydration sourdough levain on a 400g base.
To replace 6g of Fresh Cake Yeast in a 400g flour recipe (at 70% hydration / 280g liquid), use either: (1) Direct yeast equivalency (28.6g of 100% starter, deducting 14.3g flour and 14.3g liquid to leave 385.7g flour and 265.7g water); or (2) Standard 20% artisan inoculation (80g starter, leaving 360g flour and 240g water at 70% True Hydration).
- Direct Yeast Equivalent
- 28.6g StarterDeduct 14.3g flour & 14.3g 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
Gram Weights for 400g Flour Sourdough Built from 6g Fresh Cake Yeast
Compare the packet-equivalency column against the 20% baker's math column to see how much the two conventions diverge on a 400g base.
| Starter Water Ratio | Starter Weight & Hidden Flour/Water | Corrected Flour / Corrected Liquid | 20% Inoculation Weight | Corrected Flour / Corrected Liquid |
|---|---|---|---|---|
| Case 1000g @ 50% [Anchor] | 28.6g levain | subtract 19g flour, 9.5g water | 200g levain | subtract 133.3g flour, 66.7g water |
| Case 400g @ 100% One Step Down | 28.6g levain | subtract 14.3g flour, 14.3g water | 80g levain | subtract 40g flour, 40g water |
| Case 400g @ 125% One Step Up | 28.6g levain | subtract 12.7g flour, 15.9g water | 80g levain | subtract 35.6g flour, 44.4g water |
| Case 500g @ 75% Two Steps Down | 28.6g levain | subtract 16.3g flour, 12.2g water | 100g levain | subtract 57.1g flour, 42.9g water |
| Case 400g @ 100% Two Steps Up | 28.6g levain | subtract 14.3g flour, 14.3g water | 80g levain | subtract 40g flour, 40g water |
Dynamic Stoichiometric Workbench (28.6g Starter)
Test custom loaf weights or alternative fermentation schedules directly against the 80g Starter benchmark above.
Why 6g Fresh Cake Yeast Cannot Be Swapped in 400g Flour Without Deducting Starter Water
Commercial fresh cake yeast (6g) introduces negligible moisture to a 400g flour mix, whereas 80g of 100% hydration sourdough culture carries 40g fermented flour and 40g water. Deducting those exact weights keeps the 400g system at 70% hydration.
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 flour 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 (6g Fresh Cake Yeast → Sourdough in 400g Flour)
- Autolyse First: Combine 360g flour with 240g water (holding back 10% for salt) and rest 45 minutes.
- Add 80g of Ripe Levain: Pinch in the starter, add 2% salt with the reserved water, and mix until the dough is cohesive.
- Four Folds: Space two stretch and folds and two coil folds 30 minutes apart to build gluten without tearing the gas cells.
- Bulk, Shape and Retard: Reach the target rise, shape, and refrigerate 12–16 hours at 38°F before the final bake.
Key Baker's Math Questions (Direct Yeast Equivalent: 28.6g Starter)
How much sourdough starter replaces 6g of Fresh Cake Yeast in 400g flour?
By direct yeast weight equivalency, 6g of Fresh Cake Yeast equals 28.6g of 100% hydration sourdough starter. For a 400g flour batch, the 20% baker's inoculation is 80g starter.
Is a 400g sourdough conversion suitable for a pizza or focaccia base?
Yes, and long cold retarding is often an advantage for pizza. Mix 80g of levain into 360g flour and 240g water and refrigerate 24–48 hours.
How do I convert a sweet or enriched recipe with 6 g 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.