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Sourdough starter feeding ratios, explained without the mystique

By BakePen Editorial · Last updated 25 Aug 2026 · 6 min read

Few topics in baking collect folklore like sourdough starter feeding. Ratios are quoted like scripture — 1:1:1, 1:2:2, 1:5:5 — by bakers who sometimes cannot say what the numbers count, and a newcomer can be forgiven for concluding that a jar of flour and water requires a mathematics degree. It does not. Feeding ratios are one simple idea — how much food, relative to how much culture — and everything else is scheduling.

This article decodes the ratios, explains what changing them actually changes (timing and acidity, mostly), how starter hydration interacts with your dough maths, and how to keep a starter alive on a schedule that suits a person with a job.

Reading a ratio

A feeding ratio is starter : flour : water, by weight. A 1:2:2 feed takes 10 g of ripe starter and gives it 20 g of flour and 20 g of water. The first number is how much of the old culture you carry over; the other two are its meal. Bigger meals take longer to eat through, so the ratio is really a timer: 1:1:1 in a warm kitchen peaks in perhaps four hours, 1:5:5 in ten to twelve, conveniently overnight.

Notice what the ratio is not: it is not a quality grade. A starter fed 1:5:5 is not ‘stronger’ than one fed 1:1:1 in any permanent sense — both are the same culture at different points in its dinner. What changes is when it peaks and how acidic it is when it gets there, and acidity is a flavour and strength variable the baker controls precisely by choosing the ratio and the temperature together.

Peak, and why everything is timed from it

A starter is ready to raise dough at its peak: risen to its maximum, domed, full of bubbles, smelling fruity and only mildly sharp. Before the peak it is under-populated and sluggish; long after it, the culture has eaten everything, acidity has climbed, and the acids begin dismantling the very gluten your dough needs. Using starter at its peak is the closest thing sourdough has to a master rule.

Since peak time depends on ratio, temperature and the starter's own vigour, the practical skill is reading the jar, not the clock: mark the level at feeding, watch the rise curve, and note when your starter, in your kitchen, at your ratio, tops out. Two or three feedings of observation calibrate you better than any published schedule, because the variables are yours.

Starter hydration and your dough sums

Starters are kept at different hydrations — 100% (equal flour and water) is the common default; stiff starters at 50–60% are traditional for some breads and keep longer between feeds. Whatever you keep, your starter is flour and water entering the dough, and your dough's hydration maths must count it. A 100 g levain at 100% adds 50 g of each; at 60% it adds about 62 g of flour and 38 g of water.

The hydration calculator takes your starter's percentage as an input for exactly this reason. A baker who switches to a stiff starter and changes nothing else has quietly lowered the dough's hydration by several points — and will blame the flour, the weather and the moon before the jar. Count the starter, and the dough behaves as calculated.

A feeding rhythm that survives real life

The fridge is the home baker's honest friend. A starter fed, left an hour at room temperature to get started, then refrigerated, keeps a week between feeds in good health; before a bake, one or two room-temperature feeds restore full vigour. Daily counter feeding is for bakeries and the devoted; it is not a moral requirement, and a starter punished with neglect for a fortnight usually revives within two or three feeds.

What does matter: consistent flour (a change of diet unsettles a culture for a feed or two), clean jars changed regularly, and feeding by weight so the ratio — and therefore the timing — is the one you intended. A starter is not a pet and not a potion. It is an ingredient you maintain, and maintained by numbers, it is a remarkably reliable one.

Feeding ratios as timers (warm kitchen, ~24 °C)

Working backwards from bake time

Bread is wanted at Saturday noon, with mixing at 9 a.m. The starter must peak at 9. Friday evening at 9 p.m. is twelve hours earlier: a 1:5:5 feed at room temperature lands there. So Friday's jar is 10 g of starter, 50 g flour, 50 g water, mixed and left on the counter — arithmetic instead of hope. If Saturday's plan moves to a 7 a.m. mix, the same logic picks a smaller ratio or a cooler spot. Every reliable sourdough schedule in the world is this one sum, done backwards.

Common mistakes

Feeding by spoon and splash. A ‘tablespoon of starter, some flour, some water’ makes the ratio — and therefore tomorrow’s peak — unknowable. Weighing a feed takes twenty seconds.

Using starter long past its peak. Collapsed, sharp-smelling starter brings excess acid that weakens dough. If you missed the peak by hours, refresh and wait, or accept a slower, tangier loaf knowingly.

Changing flour and ratio in the same week. Two variables at once and the starter’s new timing is a mystery. Change one, observe a feed or two, then change the other.

Questions, answered

What hydration should a beginner keep a starter at?

100% — equal weights of flour and water. It is easy to measure, easy to convert in dough maths, and behaves predictably.

My starter smells of nail polish. Is it dead?

Almost certainly just hungry — that solvent smell is a classic hunger signal. Pour off, feed twice at room temperature, and judge by the rise, not the aroma of neglect.

Wholemeal or white flour for feeding?

Either works; many bakers feed a blend, since whole grains bring minerals and microbes that starters enjoy. Consistency matters more than the choice.

The short version

A starter is a culture with an appetite and a clock. Feed it by weight, choose the ratio that puts its peak at your mixing time, and count it in your dough sums, and the mystique evaporates — what remains is one of the most dependable ingredients in the kitchen.

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