Overnight 1:8:8 Sourdough Starter Feeding Ratio to Build 300g (12 - 16 hrs Peak Window)
High-dilution overnight levain math to build 300g of sweet, de-acidified starter (100% Liquid) with zero morning collapse.
The arithmetic of a 1:8:8 feeding is simple: 300 grams of starter divided by 17 parts gives 17.6g per part, so the seed is 18g, the fresh flour is 141g and the water is 141g. At 100% Liquid this extended 14-hour high-dilution de-acidifying feed build ripens in 12 - 16 hrs. If you keep a 20g jar remainder, feed 320g instead: 19g seed, 151g flour, 150g water — zero discard, permanently.
- Exact 300g Build
- 18g : 141g : 141gStarter : Flour : Water (1:8:8)
- 300g + 20g Jar Reserve
- 19g : 151g : 150gBuilds 320g total (0g discard waste)
- Estimated Peak Window
- 12 - 16 hrsAt 74°F–76°F (23.5°C–24.5°C)
- Levain Hydration
- 100%Extended 14-hour high-dilution de-acidifying feed
Reference Table: 1:8:8 Ratios at 300g and Its Neighbours
Weights derived from the 17-part 1:8:8 division, where one part equals 17.6g.
| How Much to Make | Starter (1 Part) | Flour (8 Parts) | Water (8 Parts) | Peak Hours (75°F) |
|---|---|---|---|---|
| 300g target ([Your Target]) | seed 18g | flour 141g | water 141g | ripe in 12 - 16 hrs |
| 310g target (Leaner Read) | seed 18g | flour 146g | water 146g | ripe in 12 - 16 hrs |
| 290g target (Fuller Read) | seed 17g | flour 136g | water 137g | ripe in 12 - 16 hrs |
| 320g target (Micro Scale) | seed 19g | flour 151g | water 150g | ripe in 12 - 16 hrs |
| 280g target (Large Scale) | seed 16g | flour 132g | water 132g | ripe in 12 - 16 hrs |
Live Parameter Solver for Overnight 1:8:8 Sourdough Starter Feeding
Dial in custom baker's percentages and export your adjusted 18g : 141g : 141g formula for bake day.
De-Acidifying Your Culture: Why High-Ratio 1:8:8 Feeds Maximize Oven Spring (300g Build)
Each gram of the 141g flour portion in a 1:8:8 feed absorbs roughly half its weight in water once fully hydrated, so the 141g 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 300g levain.
Flour choice shifts the timeline more than most bakers expect. At 1:8:8 with 141g of flour, a malted bread flour peaks faster and sweeter than an unmalted one, because the added amylase liberates more maltose per minute and the culture simply runs out of substrate sooner.
Zero-Discard Scraping Method for 300g Levain (1:8:8)
- Reserve the 20g Jar Remainder (19g): Tip your starter jar and scrape every last gram into a clean vessel — roughly 19g — so nothing is discarded.
- Combine the 1:8:8 Feed (151g + 150g): Stir 151g of flour into 19g of seed, then add 150g of room-temperature water until no dry flour remains.
- Mark the 320g Target: Level the jar and tape a line at the starting height; the culture should dome well past it within 12 - 16 hrs at 75°F.
- Harvest 300g and Return 20g: Pour 300g of peaked levain into your dough, then scrape the surviving 20g back into the jar and refrigerate at 38°F.
Cereal Chemistry & Bench Execution FAQs
What flour should I use for a 300g 1:8:8 levain?
A 12%+ protein bread flour for the 141g of flour gives a strong levain; adding whole wheat or rye at 20% of that weight speeds it up and adds pleasant acidity.
How many grams of starter, flour and water make 300g at a 1:8:8 ratio?
18g starter + 141g flour + 141g water = 300g, split across 17 parts of 17.6g each.
Can I still make 300g if I only have 150g of starter?
Feed 150g of seed with 141g flour and 141g water, then treat the resulting 432g of sourdough culture as your starter instead.