Sourdough feeding ratios: 1:1:1, 1:2:2, and 1:5:5
A sourdough feeding ratio is three numbers: parts of old starter, parts of flour, parts of water, all by weight. A 1:1:1 feed is 20 g of starter, 20 g of flour, 20 g of water. A 1:5:5 feed is 20 g of starter, 100 g of flour, 100 g of water. The bigger the second and third numbers, the more fresh food per unit of old starter, and the longer the starter takes to peak.
That is the whole idea. The ratio is a timer you set with a scale.
What each ratio does
| Ratio | Peak at 24C (75F) | Character | Use it when |
|---|---|---|---|
| 1:1:1 | 4-6 hours | Fast, tangy, builds acid quickly | You feed twice a day, or bake within hours |
| 1:2:2 | 6-8 hours | Balanced everyday feed | Once-a-day feeding in an average kitchen |
| 1:3:3 | 8-10 hours | Milder, slower | A warm kitchen, or a longer gap |
| 1:5:5 | 10-12 hours | Mildest, most vigorous rise | Feeding at night to bake in the morning |
| 1:10:10 | 14-18 hours | Very mild, big volume | Reviving a neglected starter, or a 24-hour gap |
Those times assume a 100% hydration starter around 24C (75F). Warmer and every row shortens, sometimes by half. Cooler and every row stretches. Feeding schedule by temperature has the temperature bands.
Work out the grams for any ratio and any amount you are keeping with the feeding-ratio calculator.
Why 1:1:1 is not automatically the default
It is the ratio most recipes name because the arithmetic is easy, but it has a real drawback: you carry a lot of acid forward. One part old starter to one part fresh flour means half the mixture is already acidic when the feed begins. Do that repeatedly in a warm kitchen and the culture drifts sour and sluggish, because the bacteria out-compete the yeast in a low-pH environment.
If your starter smells sharp, peaks fast, then collapses within a few hours, the ratio is usually the cause, not the flour. Move to 1:5:5 for three or four feeds and it typically comes back.
Picking a ratio by when you want the peak
Work backward from when you want to mix dough.
- Baking this afternoon. Feed 1:1:1 or 1:2:2 in the morning.
- Baking tomorrow morning. Feed 1:5:5 tonight before bed.
- Baking in two days. Feed 1:5:5, let it peak, then refrigerate. Take it out and feed once the night before.
- Just keeping it alive. Feed 1:5:5 once a day on the counter, or refresh once a week in the fridge.
The point of the larger ratios is not that they are better. It is that they let a peak land when you can actually use it.
Ratios and hydration are different things
The second and third numbers set hydration, not the ratio’s speed. A 1:5:5 feed is 100% hydration because flour and water are equal. A 1:5:2.5 feed is a stiff starter at 50% hydration: same amount of food, firmer texture, slower and milder result.
Keep the flour and water parts equal unless you are deliberately going stiff. More on what the percentage means: sourdough hydration explained.
How much to keep
Keep as little as you can stand. A starter that lives at 20 g needs only 100 g of flour a day at 1:5:5, produces almost no discard, and still gives you plenty to build a levain from. Most people keep far more starter than they need and then feed it grudgingly, which is how a culture ends up chronically underfed.
If you need 100 g of ripe starter for a loaf, build it the night before: keep your usual 20 g, feed it 1:5:5, and you will have 220 g at peak. Use what you need and keep 20 g back.
Changing ratio safely
Change one thing at a time and give it three feeds to settle. A starter moved from 1:1:1 to 1:5:5 will look slow on the first feed, because it is genuinely doing more work per unit of culture. By the third feed it should rise higher, peak later, and smell milder. If it does not, temperature is the next thing to check: why isn’t my starter rising.
All timings here are estimates. The reliable signal is still the jar: risen, domed, bubbly through the middle, and just about to fall.