Blog / 7 October 2026

Which feeding ratio should I use for my sourdough starter?

Pick the feeding ratio by when you need the starter, not by what the last blog you read swore by. More flour and water per gram of starter means a later peak: at 22°C, 1:1:1 peaks in about four hours, 1:5:5 in about nine, and 1:10:10 in nearly thirteen.

A ratio is written starter : flour : water, by weight. 1:5:5 with 20 g of starter is 20 g starter, 100 g flour and 100 g water.

I spent about two months trying every ratio I could find, at one point across five jars, mostly because the internet could not agree on a single one. It turns out they were all right. They were just answering different questions.

How long each ratio takes

For a starter that peaks four hours after a 1:1:1 feed, in a kitchen at 22°C:

These are the estimates Sourdough Diary starts from. They are not measurements of your jar. A lively rye starter will beat them, and a young or cold one will take its sweet time.

Why more food takes longer

The yeast and bacteria in the jar have to multiply their way through everything you gave them before the starter tops out. A small amount of starter in a lot of fresh flour starts with fewer of them per gram, so it takes longer to get there.

It does not scale one to one, though. Ten times the food does not take ten times as long, because the population keeps doubling as it goes. In the app's model the time grows with the square root of the food: four times the food, twice the time.

That is the entire trick. Nobody told me, so I am telling you.

Temperature matters more than the ratio

Ten degrees roughly doubles the speed. The 1:5:5 feed that takes about nine hours at 22°C takes a little over six at 27°C and more than twelve at 17°C.

So the same ratio does not work all year. In summer you feed a higher ratio to get the same overnight timing, and in winter a lower one. If a ratio that worked perfectly in July suddenly lets you down in November, you did nothing wrong. Your kitchen did.

How small can the amount of starter be?

Below about 10 g of starter a feed gets unreliable. A kitchen scale is a gram or two out at that weight, and a very small amount in a lot of flour is slow to get going.

That limits the high ratios when you only need a little. For 100 g of ripe starter, 1:10:10 would call for about 5 g. Sourdough Diary keeps the starter at 10 g and suggests 1:7:7 in that case: 10 g starter, 70 g flour, 70 g water.

Does the ratio change the flavour?

A little. A big feed dilutes the acid that was in the jar, so a 1:10:10 starter used at its peak is milder than a 1:1:1 starter. How far past the peak you use it changes the flavour more than the ratio ever will.

Work it out for your own jar

The starter calculator takes how much starter you need, when you need it and how warm your kitchen is, and gives you the ratio and the grams. If you are planning around a job, a schedule for a working day puts clock times on it.

In the app, the same sum runs on your own starter's timing, and it gets closer each time you tell it when the jar really peaked. Which is more than I can say for my five jars.