How to Feed a Sourdough Starter: Ratios, Schedules and Fridge Storage

 

Feeding a sourdough starter is the one habit that decides whether your bread rises or not. Get the feeding right and the starter takes care of the rest; get it wrong and even a perfect recipe will give you a flat, sour loaf. The good news is that feeding is simple once you understand the ratio, the timing, and what your starter is telling you.

The short answer

To feed a sourdough starter, discard all but a small amount of the starter, then add equal weights of flour and water — a 1:1:1 ratio by weight is the standard starting point. For example, keep 50g of starter and feed it 50g of flour and 50g of water, stir until smooth, cover loosely, and leave it at room temperature until it has at least doubled and is full of bubbles, usually 4 to 8 hours in a warm kitchen. If you bake daily, feed once or twice a day at room temperature. If you bake weekly, feed once, let it rise for an hour, and store it in the fridge, refreshing it once a week and again the day before you bake. If you are starting from zero, our day-by-day starter guide walks through the first two weeks; this post covers the ongoing routine once your starter is alive.

What feeding actually does

A sourdough starter is a colony of wild yeast and lactic acid bacteria living in flour and water. Every time you feed it, you do three things at once: you give the microbes fresh food, you dilute the acids they have produced, and you reset the population so the yeast stays ahead of the bacteria. Skip feedings and the acids build up, the yeast weakens, and the starter turns sluggish and sharply sour — the classic signs are a layer of dark liquid on top and a smell like nail polish remover. That liquid is hooch, and it is your starter asking to be fed.

Feeding by weight, not volume, is the single biggest upgrade most beginners can make. A cup of flour can weigh anywhere from 120g to 150g depending on how you scoop it, while 50g is always 50g. A cheap kitchen scale removes the guesswork from every part of sourdough, which is why weighing is the default in every CrumbPath recipe. Flour choice matters too: an unbleached all-purpose or bread flour works for daily feeding, and a spoonful of whole wheat or rye in the mix gives the microbes extra minerals to work with. Our flour guide explains which flours feed a starter best and which to avoid.

Feeding ratios explained: 1:1:1, 1:2:2, and 1:5:5

The ratio is written as starter : flour : water, always by weight. A 1:1:1 feed keeps 50g of starter and adds 50g of flour and 50g of water. It is the fastest to peak — usually 4 to 6 hours at around 75°F (24°C) — and it is the best ratio for a young starter that needs frequent attention, or for the feed right before baking, when you want maximum activity.

A 1:2:2 feed keeps 25g of starter and adds 50g of flour and 50g of water. Because there is more fresh food relative to the starter, it takes longer to peak — roughly 8 to 12 hours — and the starter stays at its peak longer. This is the workhorse ratio for most home bakers: feed in the morning, bake in the evening, or feed at night and bake in the morning.

A 1:5:5 feed keeps 10g of starter and adds 50g of flour and 50g of water. It peaks in 12 to 16 hours or more and is useful in two situations: when your kitchen is very warm and a 1:1:1 feed would peak and collapse before you get to it, and when you want to tame an overly sour starter, because the large amount of fresh flour dilutes the acids more thoroughly. The trade-off is that you discard more, and the starter spends more of the day still waking up.

There is no single correct ratio. The right one is the one that puts your starter at its peak when you need it. If your starter peaks while you are asleep and has collapsed by morning, switch to a higher ratio or a cooler spot. If it never seems to peak at all, the problem is usually temperature or flour, not the ratio — our starter-not-rising fix ladder works through those causes in order.

The daily feeding routine, step by step

First, weigh your empty jar or put your jar on the scale and press tare. Spoon out all but the amount of starter you want to keep — 50g for a 1:1:1 feed, 25g for 1:2:2. The removed starter is discard: it is perfectly good for pancakes, crackers, and flatbread, and our discard recipes put it to work instead of wasting it.

Next, add the flour and water and stir thoroughly until no dry flour remains. The consistency should be like thick pancake batter — it should fall off the spoon in a slow ribbon, not pour like water and not sit like dough. Mark the level on the jar with a rubber band or a piece of tape so you can see how far it rises. Cover loosely: a loose lid, a small plate, or a cloth cover all work, because the yeast needs to release gas and a sealed jar can build pressure. Then leave it somewhere warm and still, ideally 75 to 78°F (24 to 26°C). On top of the fridge, inside the oven with the light on, or near (not on) a warm radiator are all good spots.

How to read your starter after feeding

A healthy starter follows a predictable curve after feeding. For the first hour or two, not much seems to happen. Then small bubbles appear on the sides of the jar and the level starts to climb. At its peak it will have doubled (a strong starter often triples), the top will be domed or just flattening, and the surface will be covered in bubbles. That peak is the moment to use it in a recipe or to return it to the fridge. After the peak it collapses back down, the top goes concave, and the smell turns sharper. A collapsed starter is not dead — it is hungry — but it is past its best for baking, so feed it again before you use it.

Three signs tell you the feeding routine needs adjusting. First, if the starter rises and falls very fast — peaking in 3 hours and collapsed by 6 — your kitchen is warm or your ratio is low; move to a 1:2:2 or 1:5:5 feed. Second, if it barely rises in 12 hours, it is probably cold: move it somewhere warmer before you change anything else. Third, if it smells strongly of acetone or vinegar even right after feeding, it has been underfed for a while; give it two or three 1:2:2 feeds at room temperature, 12 hours apart, and it will usually recover. A starter that smells like fresh bread dough, yogurt, or green apple is in good shape.

Feeding schedules for how you actually bake

Daily bakers: feed once a day at room temperature with a 1:1:1 or 1:2:2 ratio, timed so the peak lines up with your mixing time. If you mix dough in the evening, feed in the morning. Many daily bakers keep a small starter — 50g total after feeding — because a small starter eats less flour and still gives you the 100g you need for a loaf.

Weekend bakers: this is the most common pattern and the one the fridge was made for. Keep the starter in the fridge between bakes and feed it once a week. The day before baking, take it out, feed it at room temperature, and let it peak. For a Saturday bake, feed on Friday evening with a 1:2:2 ratio so it is peaking on Saturday morning, or feed twice — Friday evening and Saturday morning — if the starter has been in the fridge for a full week and seems sluggish.

Twice-a-day feeding: in a hot kitchen, or when you are building up a young starter, two smaller feeds beat one large one. Feed morning and evening at 1:1:1, discarding down each time. This is also the schedule to use for a few days after rescuing a neglected starter, because frequent fresh food rebuilds the yeast population faster than one big feed.

Fridge storage: the weekly routine

The fridge slows fermentation to a crawl, which is why it is the right home for a starter you use weekly. The routine is: feed the starter, let it rise at room temperature for about an hour so the yeast gets going, then put the jar in the fridge with the lid on loosely. It will keep happily for a week, and often two, though a weekly feed keeps it stronger and less sour. When you take it out, you will often find a thin layer of hooch on top. Stir it back in for a tangier starter, or pour it off for a milder one — either is fine, and the hooch post explains the trade-off.

Never put a freshly fed, still-rising starter straight into a tightly sealed jar in the fridge. The yeast is still producing gas, and a sealed jar can build pressure. A loose lid or a jar with the seal left unclipped avoids the problem entirely. And never store a starter in the fridge for months without feeding and expect it to bounce back in one feed: it usually can be revived, but it takes three or four room-temperature feeds over two days, not one.

Common feeding mistakes

Feeding by cups instead of grams. Volume feeding is inconsistent, and inconsistency is the main reason a starter behaves differently from week to week. A scale costs less than a bag of flour and fixes this permanently.

Feeding without discarding. If you keep adding flour and water without removing any starter, the jar grows, the ratio drifts, and the starter becomes a large, sluggish mass that never peaks properly. Discard every time — or bake with it.

Using chlorinated water straight from the tap. Chlorine can slow yeast activity. If your tap water is heavily chlorinated, leave a jug uncovered overnight so the chlorine dissipates, or use filtered water. This is rarely the main problem, but it is an easy one to rule out.

Switching flours constantly. Starters adapt to a flour over several feeds. Changing flour every feed keeps the colony adjusting instead of thriving. Pick a feeding flour and stick with it for at least two weeks before judging the results.

Feeding a cold starter and expecting instant activity. A starter straight from the fridge is sluggish for the first feed back at room temperature. Give it two feeds before you judge it, and plan your bake around the second feed.

How much starter should you keep?

Less than you think. A maintenance starter of 50g after feeding is plenty: it costs about 50g of flour a day at room temperature, or 50g a week in the fridge, and you build it up the day before baking by feeding a larger ratio. To get 200g of active starter for two loaves, keep 50g and feed it 100g of flour and 100g of water (a 1:2:2 build) the night before, and it will be peaking in the morning. Keeping a huge jar on the counter is the fastest way to waste flour and dread feeding time.

One last habit makes everything easier: feed at the same time every day, or on the same day every week. Starters are forgiving of a lot, but a routine means you notice changes early — a slow rise, a new smell, a jar that peaks earlier than usual — and those early warnings are what keep a starter alive for years. Our baking schedule post shows how to fit feeding into three complete bake-day timelines, so the starter is peaking exactly when your dough needs it.

Frequently asked questions

How often should I feed my sourdough starter?

At room temperature, once a day is enough for a mature starter, twice a day in a hot kitchen or for a young starter. In the fridge, once a week keeps it healthy, plus a feed the day before you bake.

Can I feed my starter with all-purpose flour only?

Yes. Unbleached all-purpose flour works fine for daily feeding. Adding a portion of whole wheat or rye gives the microbes more minerals and often a faster rise, but it is not required.

What if I forget to feed my starter for two weeks?

Pour off any hooch, discard down to a tablespoon, and feed 1:2:2 at room temperature twice a day for two days. Most starters recover fully. If you see pink or orange streaks or fuzzy mold, discard it and start fresh.

Do I have to discard every time I feed?

Yes, unless you are building up starter for a bake. Discarding keeps the ratio — and therefore the feeding — consistent. Use the discard in recipes instead of throwing it away.

Should I feed my starter before or after putting it in the fridge?

Feed it, let it rise for about an hour at room temperature, then refrigerate. Feeding right before the fridge gives the yeast a head start and keeps the starter stronger during storage.