How to Feed a 1:1:1 Sourdough Starter Ratio to Make 40g (Same-Day 4 - 5 hrs Peak)
Fast same-day levain build math to make 40g of active starter (100% Liquid) using a 1:1:1 feeding ratio.
There are exactly 3 parts in a 1:1:1 feed. At 40g that is 13.3g per part — 13g of it is the seed culture you already own, 13g is new flour and 14g is water. Expect a 4 - 5 hrs window to full dome at 75°F. The zero-discard version builds 60g (20g / 20g / 20g) so 20g always survives in the jar. Suits Fast 4–5 hour same-day bake build.
- Exact 40g Build
- 13g : 13g : 14gStarter : Flour : Water (1:1:1)
- 40g + 20g Jar Reserve
- 20g : 20g : 20gBuilds 60g 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 40g and Its Neighbours
Weights derived from the 3-part 1:1:1 division, where one part equals 13.3g.
| How Much to Make | Starter (1 Part) | Flour (1 Parts) | Water (1 Parts) | Peak Hours (75°F) |
|---|---|---|---|---|
| 1:1:1 @ 60g [Target] | starter 20g / flour 20g | water 20g | hydration 100% Liquid | 4 - 5 hrs at 75°F |
| 1:1:1 @ 40g One Step Down | starter 13g / flour 13g | water 14g | hydration 100% Liquid | 4 - 5 hrs at 75°F |
| 1:1:1 @ 20g One Step Up | starter 7g / flour 7g | water 6g | hydration 100% Liquid | 4 - 5 hrs at 75°F |
| 1:1:1 @ 50g Two Steps Down | starter 17g / flour 17g | water 16g | hydration 100% Liquid | 4 - 5 hrs at 75°F |
| 1:1:1 @ 30g Two Steps Up | starter 10g / flour 10g | water 10g | hydration 100% Liquid | 4 - 5 hrs at 75°F |
On-Bench Hydration & Fermentation Adjuster
Modify base flour mass, levain inoculation, or ambient kitchen temperature below to recalculate from this 13g : 13g : 14g baseline.
Fast Same-Day Kinetics: Why a 1:1:1 Ratio Peaks in 4 - 5 hrs (40g Build)
Each gram of the 13g flour portion in a 1:1:1 feed absorbs roughly half its weight in water once fully hydrated, so the 14g 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 40g levain.
Shaping behaviour downstream is decided here: a levain built at 1:1:1 from 13g of seed and 13g of flour carries less residual acid than a 1:1:1 feed, so the dough it is folded into keeps more elastic recoil through bulk and produces taller oven spring.
Zero-Discard Scraping Method for 40g Levain (1:1:1)
- Never Scrap the Jar Clean: Leave a deliberate 20g remnant of culture in the vessel — this is the seed for the next 1:1:1 feed, not waste.
- Top Up with 20g Flour and 20g Water: These two additions convert your remnant into exactly 60g of 100% Liquid levain.
- Wait for the 4 - 5 hrs Peak: Confirm the dome and the escaping gas streaks before you need the levain.
- Return the Surviving 20g: Whatever levain is left after your bake goes straight back into the jar and the refrigerator, and the cycle repeats without a single discarded gram.
Common Scaling & Troubleshooting Questions (13g : 13g : 14g)
How much extra should I build so I never run out of starter?
Build 60g in total — 20g starter, 20g flour, 20g water — and the leftover 20g becomes the seed for the next feed.
How long can I keep the leftover culture in the fridge?
At 38°F (3°C) the 20g reserve rests indefinitely. Cold slows the culture without stopping it, and the 4 - 5 hrs peak simply arrives sooner once you feed it.
Why does my 1:1:1 levain smell sour instead of sweet?
Sourness means the seed was over-acidic going in. Feed 13g of fresh flour against 13g of the old starter twice in a row at 78°F and the taint disappears.