Three ingredients, one ratio, and time does the rest. Enter the target sourdough weight and choose a feeding ratio - the calculator returns exact grams of starter, flour and water plus estimated ripening time.
Sourdough Calculator - Feeding Ratios and Ripening Time
Three ingredients, one ratio, and time does the rest. Enter the target sourdough weight and choose a feeding ratio - the calculator returns exact grams of starter, flour and water plus estimated ripening time.
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Three ingredients, one ratio, and time does the rest
Every sourdough feeding comes down to three numbers: starter, flour and water. The calculator takes your target weight and chosen ratio, then returns exact grams for each component. It also factors in flour type and ambient temperature to estimate how long the starter needs to ripen before it is ready for baking.
How to use this calculator - step by step
- Target sourdough weight - how many grams of ready starter you need. Typically 100-300 g per loaf of bread.
- Feeding ratio - choose from preset ratios (1:1:1 to 1:10:10) or enter a custom one. Higher ratio = longer fermentation, milder flavor.
- Flour type (optional) - rye ferments about 25% faster than wheat. Whole wheat is about 15% faster.
- Room temperature (optional) - warmer = faster. Each degree below 24 C adds about 8% to ripening time.
- Read the results - exact grams of starter, flour and water, plus estimated ripening time and hydration percentage.
8 feeding scenarios
Situation: You keep the starter at room temperature and bake every 1-2 days. You need 150 g for tomorrow's loaf.
Result: 50 g starter + 50 g flour + 50 g water.
1:1:1 = fast ripening (4-6 h at 24 C). Ideal for daily baking.
Situation: Starter in the fridge, planning to bake in the evening. Need 200 g.
Result: 18 g starter + 91 g flour + 91 g water.
1:5:5 = 8-12 h ripening. Feed in the morning, bake in the evening. The most popular ratio among home bakers.
Situation: Starting a new sourdough culture. Need 100 g initial mix.
Result: 0 g starter (you have none) + 50 g rye flour + 50 g water.
Day 1 is just flour + water. From day 2, discard half and feed 1:1:1. The starter is ready after 5-7 days.
Situation: Baking traditional rye bread. Recipe calls for 300 g rye starter.
Result: at 1:3:3 = 43 g starter + 129 g rye flour + 129 g water.
Rye ferments faster than wheat - estimated time 6-8 h instead of 8-10 h with white wheat.
Situation: White wheat starter for light bread. Need 150 g with mild flavor.
Result: at 1:5:5 = 14 g starter + 68 g bread flour + 68 g water.
Low starter amount + white flour = mild, milky flavor. Perfect for baguettes and focaccia.
Situation: Starter has been in the fridge for 5 days. Need to wake it up. 120 g target.
Result: 24 g starter + 48 g flour + 48 g water.
After fridge storage the starter is sluggish. 1:2:2 provides enough food to restore activity in 6-8 h.
Situation: Back from vacation, starter smells like alcohol. 200 g for restart.
Result: 10 g starter + 95 g flour + 95 g water.
Minimal starter + lots of flour dilutes acetic acid. Repeat 2-3 times every 12 h and the starter will recover.
Situation: Weekend bake - 3 loaves, each needs 200 g = total 600 g.
Result: at 1:5:5 = 55 g starter + 273 g flour + 273 g water.
For large batches use a bigger jar (1-1.5 L). The starter rises 2-3x in volume and needs headroom.
Feeding ratio reference
The ratio starter:flour:water controls fermentation speed, acidity and starter strength. Higher flour ratio = longer fermentation but milder, stronger starter.
| Ratio | Ripening (24 C) | Acidity | When to use |
|---|---|---|---|
| 1:1:1 | 4-6 h | High | Daily feeding, quick turnaround |
| 1:2:2 | 6-8 h | Medium-high | Fridge revival, strong feeding |
| 1:3:3 | 8-10 h | Medium | Standard - feed every 12 h, summer heat |
| 1:5:5 | 10-14 h | Low-medium | Overnight build - feed in the evening, bake in the morning |
| 1:10:10 | 14-18 h | Low | Revival after a break, very mild flavor |
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Ready-made calculations
The most searched variants of this calculator. Each link opens it with the value already filled in, ready to calculate.
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- How much flour and water for 250 g of sourdough
- How much flour and water for 300 g of sourdough
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- How much flour and water for 500 g of sourdough