Overnight 1:5:5 Sourdough Starter Feeding Ratio to Build 300g (10 - 12 hrs Peak Window)
High-dilution overnight levain math to build 300g of sweet, de-acidified starter (100% Liquid) with zero morning collapse.
Want 300g of active levain and zero waste? Mix 27g of your existing culture with 136g flour and 137g water — a 1:5:5 ratio at 100% Liquid. Fed at 75°F the starter peaks in 10 - 12 hrs and smells sweet rather than sour. Scale up to 320g (29g seed, 145g flour, 146g water) and the extra 20g stays in the jar as tomorrow's seed. Ideal for Standard 12-hour overnight sweet-spot build.
- Exact 300g Build
- 27g : 136g : 137gStarter : Flour : Water (1:5:5)
- 300g + 20g Jar Reserve
- 29g : 145g : 146gBuilds 320g total (0g discard waste)
- Estimated Peak Window
- 10 - 12 hrsAt 74°F–76°F (23.5°C–24.5°C)
- Levain Hydration
- 100%Standard 12-hour overnight sweet-spot build
Gram-by-Gram 1:5:5 Levain Breakdown for 300g (100% Liquid)
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 (5 Parts) | Water (5 Parts) | Ripening Time |
|---|---|---|---|---|
| 300g 1:5:5 levain [Baseline] | 27g seed culture | 136g flour | 137g water | peak 10 - 12 hrs |
| 290g 1:5:5 levain Trimmed Read | 26g seed culture | 132g flour | 132g water | peak 10 - 12 hrs |
| 310g 1:5:5 levain Extended Read | 28g seed culture | 141g flour | 141g water | peak 10 - 12 hrs |
| 280g 1:5:5 levain Compact Read | 25g seed culture | 127g flour | 128g water | peak 10 - 12 hrs |
| 320g 1:5:5 levain Generous Read | 29g seed culture | 145g flour | 146g water | peak 10 - 12 hrs |
Live Parameter Solver for Overnight 1:5:5 Sourdough Starter Feeding
Dial in custom baker's percentages and export your adjusted 27g : 136g : 137g formula for bake day.
De-Acidifying Your Culture: Why High-Ratio 1:5:5 Feeds Maximize Oven Spring (300g Build)
A 1:5:5 feed at 300 g is really a statement about how much acid you want to inherit. At 1:5:5, the 27.3g-per-part arithmetic places 27g of already-acidified culture into 136g of virgin flour plus 137g of water, and that dilution ratio governs the final pH of your levain.
Shaping behaviour downstream is decided here: a levain built at 1:5:5 from 27g of seed and 136g 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 300g Levain (1:5:5)
- Feed at the Right Moment: For standard 12-hour overnight sweet-spot build, begin the 1:5:5 feed 10 - 12 hrs before you plan to mix dough.
- Mix 29g Seed, 145g Flour, 146g Water: Combine everything in the jar and swirl until the flour is fully hydrated.
- Cover and Rest (10 - 12 hrs): Keep the jar at 75°F, ideally inside a proofing box, until the culture peaks.
- Use 300g and Keep 20g: The levain goes into your dough at full stretch; the reserve becomes the next cycle's 1:5:5 seed.
Cereal Chemistry & Bench Execution FAQs
Should the water be warm or cold for a 1:5:5 feed?
Room temperature, roughly 70°F (21°C). Hotter water risks shocking the culture, while colder water stretches the 10 - 12 hrs peak considerably.
How long can I keep the leftover starter in the fridge?
At 38°F (3°C) the 20g reserve rests indefinitely. Cold slows the culture without stopping it, and the 10 - 12 hrs peak simply arrives sooner once you feed it.
Does the 300g figure include the jar remnants?
No. 300g is the usable levain you take out of the jar; the jar build is 320g so that 20g of culture always survives the transfer.