Sourdough starter feeding calculator
Enter how much starter you want to end up with and the feeding ratio, and get the grams of ripe starter, flour and water — plus a rough time to peak at your kitchen temperature.
Mix 10.9 g starter + 54.5 g flour + 54.5 g water
Feeding amounts by ratio
each part = target ÷ (starter + flour + water parts). Grams of ripe starter / flour / water for common targets:
| Target | 1 : 1 : 1 | 1 : 2 : 2 | 1 : 5 : 5 | 1 : 10 : 10 |
|---|---|---|---|---|
| 50 g | 17 / 17 / 17 | 10 / 20 / 20 | 5 / 23 / 23 | 2 / 24 / 24 |
| 100 g | 33 / 33 / 33 | 20 / 40 / 40 | 9 / 45 / 45 | 5 / 48 / 48 |
| 150 g | 50 / 50 / 50 | 30 / 60 / 60 | 14 / 68 / 68 | 7 / 71 / 71 |
| 200 g | 67 / 67 / 67 | 40 / 80 / 80 | 18 / 91 / 91 | 10 / 95 / 95 |
| 300 g | 100 / 100 / 100 | 60 / 120 / 120 | 27 / 136 / 136 | 14 / 143 / 143 |
| 500 g | 167 / 167 / 167 | 100 / 200 / 200 | 45 / 227 / 227 | 24 / 238 / 238 |
Rough time to peak by temperature
Estimated hours for a mature 100% hydration starter fed white or mostly white flour. The model assumes about 4 h at 1 : 1 : 1 and 72°F (22°C), longer at higher ratios (4 + 3.4 × ln of the flour multiple) and about twice as long for every 8°C (14°F) cooler. It matches the ranges bakers commonly report, but starters differ — use it to choose a ratio, then watch the jar.
| Room | 1 : 1 : 1 | 1 : 2 : 2 | 1 : 5 : 5 | 1 : 10 : 10 |
|---|---|---|---|---|
| 64°F (18°C) | ≈ 5.7 h | ≈ 9 h | ≈ 13.4 h | ≈ 16.7 h |
| 68°F (20°C) | ≈ 4.8 h | ≈ 7.6 h | ≈ 11.3 h | ≈ 14.1 h |
| 72°F (22°C) | ≈ 4 h | ≈ 6.4 h | ≈ 9.5 h | ≈ 11.8 h |
| 75°F (24°C) | ≈ 3.4 h | ≈ 5.3 h | ≈ 8 h | ≈ 9.9 h |
| 79°F (26°C) | ≈ 2.8 h | ≈ 4.5 h | ≈ 6.7 h | ≈ 8.4 h |
| 82°F (28°C) | ≈ 2.4 h | ≈ 3.8 h | ≈ 5.6 h | ≈ 7 h |
Choosing a ratio
- 1 : 1 : 1 — fastest; good for a warm-up feed, a sluggish or young starter, or a cold kitchen.
- 1 : 2 : 2 — the everyday feed for baking the same day: feed in the morning, mix in the afternoon.
- 1 : 5 : 5 — the overnight feed: feed at bedtime, mix after breakfast. Also milder in flavor because the starter spends less time over-ripe.
- 1 : 10 : 10 — for long gaps or hot kitchens, such as a 12-hour workday or summer nights.
To keep waste down, maintain a small seed (20–50 g) and build only what the recipe needs plus 10–20 g. The full reasoning, with a worked example, is in how much to feed a sourdough starter. Then use the sourdough hydration calculator or the sourdough bread formula to put the levain to work.
FAQ
What is the best sourdough starter feeding ratio?
The one that makes your starter peak when you need it. At about 72°F (22°C) a mature starter fed 1 : 1 : 1 peaks in roughly 3–5 hours, 1 : 2 : 2 in 5–8 hours, 1 : 5 : 5 in 8–12 hours and 1 : 10 : 10 in 12–16 hours.
How much flour and water do I feed 50 g of starter?
At 1 : 1 : 1 add 50 g flour and 50 g water; at 1 : 2 : 2, 100 g each; at 1 : 5 : 5, 250 g each. Usually it is better to discard down to a smaller seed first and build only the amount you need.
Does the amount of starter change the peak time?
Very little. The ratio of old starter to fresh flour and the temperature decide the timing; 20 g and 200 g at the same ratio peak at about the same time.