How to Feed a 1:2:2 Sourdough Starter Ratio to Make 100g (Same-Day 6 - 8 hrs Peak)
Fast same-day levain build math to make 100g of active starter (100% Liquid) using a 1:2:2 feeding ratio.
To make 100g of active culture at a 1:2:2 ratio (1:2:2), weigh 20g of ripe seed, 40g of flour and 40g of water. That 100% Liquid culture will be domed and sweet in 6 - 8 hrs at 75°F, which is exactly the timing you want for Balanced 6–8 hour morning levain build. Feed 120g — 24g / 48g / 48g — if you want to stop discarding permanently.
- Exact 100g Build
- 20g : 40g : 40gStarter : Flour : Water (1:2:2)
- 100g + 20g Jar Reserve
- 24g : 48g : 48gBuilds 120g total (0g discard waste)
- Estimated Peak Window
- 6 - 8 hrsAt 74°F–76°F (23.5°C–24.5°C)
- Levain Hydration
- 100%Balanced 6–8 hour morning levain build
Gram-by-Gram 1:2:2 Levain Breakdown for 100g (100% Liquid)
Comparison of 1:2:2 builds either side of 100g, with ripening windows quoted at 75°F (24°C).
| Target Build Weight | Ripe Seed (1) | New Flour (2) | Liquid (2) | Time to Full Dome |
|---|---|---|---|---|
| 100g target ([Target]) | seed 20g | flour 40g | water 40g | ripe in 6 - 8 hrs |
| 110g target (One Step Down) | seed 22g | flour 44g | water 44g | ripe in 6 - 8 hrs |
| 90g target (One Step Up) | seed 18g | flour 36g | water 36g | ripe in 6 - 8 hrs |
| 120g target (Two Steps Down) | seed 24g | flour 48g | water 48g | ripe in 6 - 8 hrs |
| 80g target (Two Steps Up) | seed 16g | flour 32g | water 32g | ripe in 6 - 8 hrs |
Custom Batch Recalculation Engine
Fine-tune starter hydration between 50% stiff and 125% liquid while keeping your starter feeding ratio × target weight ratios locked.
Fast Same-Day Kinetics: Why a 1:2:2 Ratio Peaks in 6 - 8 hrs (100g Build)
Scaling to 100g means every gram is shared across 5 parts (20.0g each). The 20g seed portion carries the entire wild yeast and lactobacilli population, the 40g flour portion supplies the substrate, and the 40g water portion sets the mobile phase for both.
Readiness, not the clock, should end the feed. The 1:2:2 culture at 100 g should dome into a taut convex pillow and release gas in visible streaks when the jar is tilted; a levain that merely doubled and stayed flat has not finished fermenting and will underproof the dough.
Zero-Discard Scraping Method for 100g Levain (1:2:2)
- Check Room Temperature: Confirm your kitchen is close to 75°F (24°C). At 68°F a 1:2:2 feed stretches toward 6 - 8 hrs of extra ripening, and at 82°F it contracts noticeably.
- Build the 120g Base (24g Seed): Feed your seed starter with 48g of flour and 48g of water at 100% Liquid.
- Watch for the Convex Dome (6 - 8 hrs): The surface should bulge into a smooth pillow and jiggle when gently shaken, not collapse flat.
- Split the Peak (100g Out, 20g Back): Use 100g of the 120g build in your dough and restart the cycle with the 20g that is left.
Technical Q&A: How to Feed a 1:2:2 Sourdough Starter Ratio to M
What is the real difference between 1:2:2 and a 1:1:1 feed?
A 1:1:1 feed keeps one third of the batch as seed and peaks fastest; 1:2:2 keeps one 5th, so it ripens more slowly but with far less inherited acidity.
What flour should I use for a 100g 1:2:2 levain?
A 12%+ protein bread flour for the 40g of flour gives a strong levain; adding whole wheat or rye at 20% of that weight speeds it up and adds pleasant acidity.
How much extra should I build so I never run out of starter?
Build 120g in total — 24g starter, 48g flour, 48g water — and the leftover 20g becomes the seed for the next feed.