How to Build 40g of 1:3:2 Semi-Stiff (67%) Sourdough Starter (7g Seed, 20g Flour, 13g Water)
Low-hydration stiff levain math (67% Semi-Stiff Levain) to build 40g of sweet, low-acidity starter for artisan bread or enriched dough.
To make 40g of active starter at a 1:3:2 Semi-Stiff (67%) ratio (1:3:2), weigh 7g of ripe seed, 20g of flour and 13g of water. That 67% Semi-Stiff Levain culture will be domed and sweet in 8 - 10 hrs at 75°F, which is exactly the timing you want for High-elasticity creamy crumb stiff sourdough culture build. Feed 60g — 10g / 30g / 20g — if you want to stop discarding permanently.
- Exact 40g Build
- 7g : 20g : 13gStarter : Flour : Water (1:3:2 Semi-Stiff (67%))
- 40g + 20g Jar Reserve
- 10g : 30g : 20gBuilds 60g total (0g discard waste)
- Estimated Peak Window
- 8 - 10 hrsAt 74°F–76°F (23.5°C–24.5°C)
- Levain Hydration
- 67%High-elasticity creamy crumb stiff levain build
Reference Table: 1:3:2 Semi-Stiff (67%) Ratios at 40g and Its Neighbours
Zero-waste gram breakdown for 1:3:2 Semi-Stiff (67%) (67% Semi-Stiff Levain) centred on the 40g target, with the 60g jar reserve alongside.
| Target Levain Yield | Seed Starter (1 Part) | Fresh Flour (3 Parts) | Water (2 Parts) | Peak Ripening Time @ 75°F |
|---|---|---|---|---|
| 40g target ([Your Target]) | seed 7g | flour 20g | water 13g | ripe in 8 - 10 hrs |
| 50g target (Leaner Read) | seed 8g | flour 25g | water 17g | ripe in 8 - 10 hrs |
| 30g target (Fuller Read) | seed 5g | flour 15g | water 10g | ripe in 8 - 10 hrs |
| 60g target (Micro Scale) | seed 10g | flour 30g | water 20g | ripe in 8 - 10 hrs |
| 20g target (Large Scale) | seed 3g | flour 10g | water 7g | ripe in 8 - 10 hrs |
On-Bench Hydration & Fermentation Adjuster
Modify base flour mass, levain inoculation, or ambient kitchen temperature below to recalculate from this 7g : 20g : 13g baseline.
How 1:3:2 Semi-Stiff (67%) Hydration Shifts Lactic-to-Acetic Fermentation in a 40g Build
Flour quality matters more than ratio labels at this size: 20g of fresh flour feeding 7g of seed at 67% Semi-Stiff Levain determines how much maltose the amylase releases per hour, which in turn sets the 8 - 10 hrs ripening curve at 75°F.
Watch the jar wall. A 40g build in a straight-sided container rises almost exactly in proportion to its weight because 67% Semi-Stiff Levain levain traps little gas structure; mark the starting line with a rubber band and you can read the 8 - 10 hrs window without guessing.
Zero-Discard Scraping Method for 40g Levain (1:3:2 Semi-Stiff (67%))
- Check Room Temperature: Confirm your kitchen is close to 75°F (24°C). At 68°F a 1:3:2 Semi-Stiff (67%) refresh stretches toward 8 - 10 hrs of extra ripening, and at 82°F it contracts noticeably.
- Build the 60g Base (10g Seed): Feed your seed starter with 30g of flour and 20g of water at 67% Semi-Stiff Levain.
- Watch for the Convex Dome (8 - 10 hrs): The surface should bulge into a smooth pillow and jiggle when gently shaken, not collapse flat.
- Split the Peak (40g Out, 20g Back): Use 40g of the 60g build in your dough and restart the cycle with the 20g that is left.
Common Scaling & Troubleshooting Questions (7g : 20g : 13g)
What flour should I use for a 40g 1:3:2 Semi-Stiff (67%) sourdough culture?
A 12%+ protein bread flour for the 20g of flour gives a strong sourdough culture; adding whole wheat or rye at 20% of that weight speeds it up and adds pleasant acidity.
Should the water be warm or cold for a 1:3:2 Semi-Stiff (67%) feed?
Room temperature, roughly 70°F (21°C). Hotter water risks shocking the culture, while colder water stretches the 8 - 10 hrs peak considerably.
Why is my 1:3:2 Semi-Stiff (67%) starter not doubling?
Usually the seed was neglected in the refrigerator. Two warm 1:2:2 refreshes at 76–78°F, each with 20g of fresh flour, will strip the acid and restart the yeast.