How to Feed a 1:1:1 Sourdough Starter Ratio to Make 300g (Same-Day 4 - 5 hrs Peak)
Fast same-day levain build math to make 300g of active starter (100% Liquid) using a 1:1:1 feeding ratio.
Feed 1:1:1 and you get 100g seed culture, 100g flour and 100g water, adding up to the 300g you actually need. That 100% Liquid culture peaks in 4 - 5 hrs at 75°F. Add the 20g buffer and the numbers shift to 107g / 107g / 106g for a 320g jar. Perfect for Fast 4–5 hour same-day bake build.
- Exact 300g Build
- 100g : 100g : 100gStarter : Flour : Water (1:1:1)
- 300g + 20g Jar Reserve
- 107g : 107g : 106gBuilds 320g total (0g discard waste)
- Estimated Peak Window
- 4 - 5 hrsAt 74°F–76°F (23.5°C–24.5°C)
- Levain Hydration
- 100%Fast 4–5 hour same-day bake build
Reference Table: 1:1:1 Ratios at 300g and Its Neighbours
Weights derived from the 3-part 1:1:1 division, where one part equals 100.0g.
| How Much to Make | Starter (1 Part) | Flour (1 Parts) | Water (1 Parts) | Peak Hours (75°F) |
|---|---|---|---|---|
| 290g 1:1:1 levain [Baseline] | 97g seed culture | 97g flour | 96g water | peak 4 - 5 hrs |
| 320g 1:1:1 levain Trimmed Read | 107g seed culture | 107g flour | 106g water | peak 4 - 5 hrs |
| 300g 1:1:1 levain Extended Read | 100g seed culture | 100g flour | 100g water | peak 4 - 5 hrs |
| 280g 1:1:1 levain Compact Read | 93g seed culture | 93g flour | 94g water | peak 4 - 5 hrs |
| 310g 1:1:1 levain Generous Read | 103g seed culture | 103g flour | 104g water | peak 4 - 5 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 1:1:1 Ratio Peaks in 4 - 5 hrs (300g Build)
Each gram of the 100g flour portion in a 1:1:1 feed absorbs roughly half its weight in water once fully hydrated, so the 100g water portion at 100% Liquid sits exactly where the flour becomes a pourable paste rather than a shaggy mass — the consistency you want in a 300 grams levain.
Timing your bake around the feed is what makes a 1:1:1 build useful: count backwards from your target oven time by 4 - 5 hrs plus your bulk duration, and you arrive at the moment you should stir 100g of flour into 100g of water for fast 4–5 hour same-day bake build.
Zero-Discard Scraping Method for 300g Levain (1:1:1)
- Check Room Temperature: Confirm your kitchen is close to 75°F (24°C). At 68°F a 1:1:1 feed stretches toward 4 - 5 hrs of extra ripening, and at 82°F it contracts noticeably.
- Build the 320g Base (107g Seed): Feed your seed starter with 107g of flour and 106g of water at 100% Liquid.
- Watch for the Convex Dome (4 - 5 hrs): The surface should bulge into a smooth pillow and jiggle when gently shaken, not collapse flat.
- Split the Peak (300 g Out, 20g Back): Use 300 g of the 320g build in your dough and restart the cycle with the 20g that is left.
Technical Q&A: How to Feed a 1:1:1 Sourdough Starter Ratio to M
How much extra should I build so I never run out of starter?
Build 320g in total — 107g starter, 107g flour, 106g water — and the leftover 20g becomes the seed for the next feed.
Why does my 1:1:1 levain smell sour instead of sweet?
Sourness means the seed was over-acidic going in. Feed 100g of fresh flour against 100g of the old starter twice in a row at 78°F and the taint disappears.
What happens if I use 1:1:1 starter in a very wet dough?
The 100% Liquid levain carries less acid, so a wet dough keeps more of its elasticity. Hold back a little extra water if your flour absorbs like 100g of bread flour does.