How to Feed a 1:2:2 Sourdough Starter Ratio to Make 120g (Same-Day 6 - 8 hrs Peak)
Fast same-day levain build math to make 120g of active starter (100% Liquid) using a 1:2:2 feeding ratio.
To make 120g of active starter at a 1:2:2 ratio (1:2:2), weigh 24g of ripe seed, 48g of flour and 48g 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 140g — 28g / 56g / 56g — if you want to stop discarding permanently.
- Exact 120g Build
- 24g : 48g : 48gStarter : Flour : Water (1:2:2)
- 120g + 20g Jar Reserve
- 28g : 56g : 56gBuilds 140g 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
1:2:2 Sourdough Starter Feeding Chart Around a 120g Build
Peak ripening estimates assume a 75°F kitchen and 23°C room; colder kitchens need roughly 3.8% more time per degree.
| Build This Much | Seed (1 Part) | Flour (2 Parts) | Water (2 Parts) | Ripening Time |
|---|---|---|---|---|
| 100g 1:2:2 ([Target]) | seed 20g | fresh flour 40g | room-temp water 40g | peak 6 - 8 hrs at 75°F |
| 120g 1:2:2 (One Step Down) | seed 24g | fresh flour 48g | room-temp water 48g | peak 6 - 8 hrs at 75°F |
| 140g 1:2:2 (One Step Up) | seed 28g | fresh flour 56g | room-temp water 56g | peak 6 - 8 hrs at 75°F |
| 110g 1:2:2 (Two Steps Down) | seed 22g | fresh flour 44g | room-temp water 44g | peak 6 - 8 hrs at 75°F |
| 130g 1:2:2 (Two Steps Up) | seed 26g | fresh flour 52g | room-temp water 52g | peak 6 - 8 hrs at 75°F |
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 (120g Build)
Monod growth kinetics explain the 6 - 8 hrs window: the 1:2:2 feed drops the seed fraction to 24.0g per 5 parts, so fermentable sugar concentration sits just above the half-saturation constant for 24g of inoculum. Yeast divides fastest while sugar is plentiful, then slows as the 48g of new flour is exhausted and lactic acid accumulates.
Retard the leftover, not the levain. The 6 - 8 hrs peak at 100% Liquid is a room-temperature event; once you have used your 120g, park the remaining 20g of the 140g build in the refrigerator at 38°F, where the culture rests without consuming its own starch supply.
Zero-Discard Scraping Method for 120g Levain (1:2:2)
- Reserve the 20g Jar Remainder (28g): Tip your starter jar and scrape every last gram into a clean vessel — roughly 28g — so nothing is discarded.
- Combine the 1:2:2 Feed (56g + 56g): Stir 56g of flour into 28g of seed, then add 56g of room-temperature water until no dry flour remains.
- Mark the 140g Target: Level the jar and tape a line at the starting height; the culture should dome well past it within 6 - 8 hrs at 75°F.
- Harvest 120g and Return 20g: Pour 120g of peaked sourdough culture into your dough, then scrape the surviving 20g back into the jar and refrigerate at 38°F.
Technical Q&A: How to Feed a 1:2:2 Sourdough Starter Ratio to M
How many grams of starter, flour and water make 120g at a 1:2:2 ratio?
24g starter + 48g flour + 48g water = 120g, split across 5 parts of 24.0g each.
How long does a 1:2:2 refreshing take to peak?
At 75°F (24°C) the culture domes in 6 - 8 hrs; a cooler room adds roughly 3.8% for every degree below that.
Can I scale this 120g build up to 240g?
Double every number: 48g starter, 96g flour, 96g water. The ratio, and therefore the 6 - 8 hrs peak, is unchanged.