How to Convert 180g Stiff Sourdough Starter (50% Hydration) to Commercial Yeast
Restoring +120g flour and +60g water when replacing 180g of 50% stiff levain with dry or fresh yeast.
Think of the swap as a bookkeeping exercise, not a formula change. 180g of 50% starter is not 180g of nothing — it is 120g of flour and 60g of water that you are about to delete. Put them back, and the dough returns to 570g flour and 375g water at 65.8% hydration, now leavened by 8g of instant yeast for a 1.5 – 2.0 hours warm bulk rise.
- Add Back Flour
- +120gReplaces flour inside 180g (50%) starter
- Add Back Water
- +60gReplaces water inside 180g (50%) starter
- Instant Yeast (2-Hr Rise)
- 8g (2.6 tsp)For 570g total flour batch
- Preserved Hydration
- 65.8%375g W / 570g F
Gram Weights for Replacing 180g of 50% Hydration Starter
Calculated on a 450g main flour + 120g restored starter flour (570g total flour) batch.
| Target Fermentation Schedule | Instant Dry Yeast (IDY) | Active Dry Yeast (ADY) | Fresh Compressed Yeast | Required Dough Restoration |
|---|---|---|---|---|
| 160g 50% starter — Standard Same-Day (1.5–2 hrs) [Your Batch] | use 7.8g instant | use 9.7g active dry | use 23.4g fresh | add 106.7g flour + 53.3g water |
| 180g 50% starter — Slow Artisan Bulk (3.5–4.5 hrs) Scaled Down | use 4g instant | use 5g active dry | use 12g fresh | add 120g flour + 60g water |
| 200g 50% starter — Overnight No-Knead / Cold Proof (12–18 hrs) Scaled Up | use 1.5g instant | use 1.8g active dry | use 4.4g fresh | add 133.3g flour + 66.7g water |
| 170g 50% starter — Standard Same-Day (1.5–2 hrs) Trimmed | use 7.9g instant | use 9.9g active dry | use 23.7g fresh | add 113.3g flour + 56.7g water |
| 190g 50% starter — Slow Artisan Bulk (3.5–4.5 hrs) Expanded | use 4g instant | use 5g active dry | use 12.1g fresh | add 126.7g flour + 63.3g water |
Real-Time Dough & Starter Scaling Sandbox
Scale this Convert 180g Stiff Sourdough Levain specification up or down on your digital scale with zero hydration drift.
Decomposing 180g of 50% Stiff Levain: High-Flour Mass Conservation
Deleting 180g of 50% starter without adding back 120g grain and 60g water shrinks loaf volume and distorts the 65.8% hydration ratio across the 570g batch.
Shelf life shortens. The 65.8% hydration dough leavened by 8g of yeast stales faster than the levain version, because there is no residual acid to slow starch retrogradation.
Step-by-Step Reverse Conversion Protocol (180g @ 50%)
- Audit the Original Formula: Confirm the recipe's yeast was the only leavening, and that the 180g of 50% starter was the sole source of the 120g of hidden flour.
- Rebuild at Full Scale: The batch is now 570g flour and 375g liquid — the same numbers as before, minus the starter.
- Dose for the Schedule You Want: 8g (2.6 tsp) of instant yeast for a 1.5 – 2.0 hours warm bulk rise; use about a fifth of that for a cold overnight ferment.
- Bake and Compare: The crumb will be lighter and less acid-forward, but the volume and crust colour should be close to the levain original.
Diagnostic Answers: Convert 180g Stiff Sourdough Levain (50% Hyd
Does the converted dough keep the same dough weight?
Almost — the 180 grams of starter is replaced by the 8g of yeast plus the 120g of flour and 60g of water you put back, which is a slightly different total.
Will my converted dough taste different from the levain version?
Yes. The roughly 4g of residual acid inside 180 g of starter was providing both flavour and tenderising, and commercial yeast replaces neither.
What happens to the batch's hydration when I swap out 180g of starter?
Nothing, provided you restore the 120g of flour and 60g of water inside it. The batch stays at 65.8% true hydration on 570g of total flour.