How to Feed a Sourdough Starter

Feed a sourdough starter once a day at room temperature, or once a week in the fridge. Each feed is equal weights of flour, water and existing starter — the classic 1:1:1 ratio that works in almost every UK kitchen. In a cool 18°C room, that feed will peak in 8–10 hours; in a warm 24°C kitchen, closer to 4. This guide walks through the schedule, the ratios, and the seven signs your starter has been fed correctly.

When does a starter actually need feeding? (the signs)

We don't feed a starter on a schedule, exactly. We feed it when it tells us to. The schedule is just our best guess at when it usually will. A healthy starter is on a cycle: feed, climb, peak, plateau, fall. Feed it when it's near the bottom of the fall, and it climbs again. Feed it at the top of the climb, and you waste the energy you've already built. Feed it after a long, hungry day, and it climbs slower the next time.

That cycle is the whole game. Everything else in this guide is just maths around it.

Peak — and the slow fall back down

Peak is the moment your starter has roughly doubled in the jar, the top is gently domed, the side is freckled with bubbles, and it smells like ripe yoghurt with a faint hint of green apple. After peak — over the next 4 to 12 hours — it loses the dome, sinks back to where it started, and the smell sharpens from yoghurty to vinegary. None of that is bad. It's hungry, not dying.

The hooch layer, and what it means

Hooch is the thin, grey-to-dark liquid that pools on top of an over-hungry starter. It's just water and alcohol — a by-product of fermentation when there's nothing left to eat. Pour most of it off, give the starter a stir, discard down to 20 g, and feed at 1:1:1. By the next morning, the bubbles are usually back. We've never had a Somerset-kitchen starter we couldn't bring back from hooch in two feeds.

The daily-feed schedule (room-temperature starter)

How often should I feed a sourdough starter?

Feed a sourdough starter once every 24 hours when you keep it at room temperature, or once a week when you store it in the fridge. In a warm UK kitchen above 22°C, twice a day can help in the height of summer. A starter that's been refrigerated for longer than a week is usually still rescuable — feed it, wait, feed it again, and watch for bubbles within 24 hours.

If you bake at least once a week — or you're in the run-up to your first loaf — keep your starter on the kitchen counter and feed it once a day.

A typical UK kitchen day, by the clock

Here is what a daily-feed day looks like in a kitchen at around 20°C:

• 08:00 — pull the jar off the counter. Notice it's gently domed or just past peak.
• 08:05 — tip most of it into a clean jar marked "discard, for crackers" and pop that in the fridge. Leave 20 g in the original jar.
• 08:06 — add 20 g of strong white bread flour and 20 g of cool tap water (around 18–22°C). Stir with a teaspoon until smooth. Rubber band around the jar at the top of the starter.
• 08:07 — loose lid on, leave on the counter.
• By 16:00 — visibly climbing, lots of bubbles, smell going sweet.
• By 19:00–20:00 — at peak. If you're baking that night, use it now.
• By 08:00 the next morning — sunk back to the rubber band line, time to feed again.

When to skip a feed, when to double up

Can I feed my starter twice a day?

Yes — feed a sourdough starter twice a day when your kitchen is above 22°C, when you're building strength before a bake, or when peaks are coming and going within 4 hours. Use the same 1:1:1 ratio for each feed. Twice-daily feeds aren't compulsory the rest of the year; once a day is plenty for a starter you bake with weekly in a UK kitchen at 18–22°C.

Skip a feed if your starter is still domed and fragrant 24 hours later — that usually means your kitchen has cooled (a damp British November). Wait until it sinks, then feed. Double up if your starter is sinking within 6 hours (a hot August kitchen at 26°C). Feed once at breakfast and once at supper. Or move to 1:3:3 (see below) and stay on a single daily feed.

The fridge-feed schedule (the once-a-week starter)

If you bake every weekend or less, the fridge is your friend.

Before you put it in: feed and wait

Don't put a hungry starter in the fridge. Feed it, leave it on the counter for 2 to 4 hours until it's starting to climb but well short of peak, then lid it loosely and slide it onto a middle fridge shelf. That captive momentum lasts the week.

Bringing it back out: the wake-up routine

A week later, the starter looks flat, sometimes with a thin hooch. Pour off the hooch, stir, discard to 20 g, feed at 1:1:1, leave on the counter. Within 4 to 8 hours it should be domed and bubbling — that's your bake-ready starter. If it's slow on the first feed (which is normal after a long fridge stretch), feed it a second time once it's peaked and fallen.

The classic 1:1:1 ratio — and why most kitchens want it

What is the ratio for feeding sourdough starter?

The classic feeding ratio for a sourdough starter is 1:1:1 by weight — one part mature starter, one part flour, one part water. For example, keep 20 g of starter, then add 20 g of strong white bread flour and 20 g of water. In slow or cold UK kitchens, switch to 1:3:3 (the slowest common ratio): 20 g of starter, 60 g flour, 60 g water — it stretches a feed to 24 hours comfortably.

The math is easy, the volumes stay manageable, and in a UK kitchen at 18–22°C it cycles in roughly 12 hours — which is the magic number for a once-daily feed. A worked example: keep 20 g of mature starter in the jar. Add 20 g of strong white bread flour and 20 g of room-temperature water. Stir. That's it. By morning, you've got 60 g of fed starter — enough for almost any home loaf (most need 50–80 g of leaven), with a little left over to feed again.

Alternative ratios — 1:3:3, 1:5:5, and when to use them

We love the 1:1:1 default, but it isn't the only ratio. The bigger the feed relative to the starter, the longer it takes the new bacteria and yeasts to consume it — which means a slower peak and a calmer starter between feeds. (For the maths and the pH science behind this, see Buehler's Bread Science, the standard reference on starter pH evolution.)

1:3:3 — for slow kitchens or weekend bakers

The 1:3:3 rule means one part starter to three parts flour to three parts water by weight. Twenty grams of starter, sixty grams of flour, sixty grams of water. Peak comes around 18–24 hours later in a UK kitchen, which is perfect for a single daily feed in a cool home — or for a weekend baker who wants the starter at its best on Saturday morning. We've got a dedicated explainer for this one — see the 1/3/3 rule explained.

1:5:5 — for hot kitchens or longer gaps

The 1:5:5 ratio stretches the gap further still — closer to 36 hours at 20°C. Useful in high summer, or if you're somewhere like a glass-roofed kitchen extension on a hot July afternoon. It produces a very mild, sweet starter — good for milk breads and brioche, less good for that punchy classic sourdough tang.

Feeding by weight, not volume

Cups don't work for sourdough. A cup of flour weighs anywhere from 120 g to 160 g depending on how you scoop, and that variability is enough to throw a 1:1:1 ratio out by 40%. A pair of cheap digital kitchen scales (under £15) is the single best investment you'll make for sourdough. Set the scales to grams, tare to zero after each addition. That's the whole technique.

What "fed and ready" actually looks like

Four signals, in order of reliability:

1. Doubled in volume. Mark the starting line with a rubber band. When the starter has hit twice that line, it's ready.
2. Domed top. A healthy peak is gently domed, not flat or collapsed.
3. Ripe-yoghurt smell. Sweet-tangy. If it smells of vinegar or nail polish, see Troubleshooting below.
4. Bubbles visible through the side of the jar — not just on top.

The float test, honestly

The float test — drop a teaspoon of starter into water; if it floats, it's ready — works for 100% hydration white starters and is unreliable for stiff starters or rye. Use the four signals above first. The float test is a confirmer, not a decider.

Smell, dome and bubble pattern

The smell ladder: sweet → ripe yoghurt → green apple → vinegar → nail polish. Sweet means under-fermented. Ripe yoghurt and green apple are the peak window. Vinegar means past peak (still fine to bake with). Nail polish means it's been starved for days — feed it twice before using.

Feed Schedule Calculator

Tell us your kitchen temperature and how much starter you keep. We'll work out the schedule, the feed amounts, and when your next peak should land.

Starter activity curve — what 24 hours after a feed looks like

Volume against hours since feed, for three kitchen temperatures. Notice how the warmer line peaks earlier and falls earlier — that's why a 26°C kitchen wants two feeds a day, and an 18°C kitchen wants one.

Troubleshooting a sluggish starter

Smells like nail polish or paint thinner

That's acetone — the sign of a starter that's been hungry for days. It's not broken. Discard down to 20 g, feed at 1:1:1, leave 12 hours, feed again. After two feeds it should be back to ripe yoghurt.

Sharp vinegar, with no rise

Sharp vinegar plus no rise usually means the bacteria are dominant and the yeasts are exhausted. Feed once or twice with wholemeal or rye flour to wake the yeast back up — the extra minerals give the wild yeast a leg-up.

Bubbles, but no real climb

Bubbles without rise usually means the gluten is weak (sometimes from chlorinated low-protein supermarket plain flour). Switch to a UK strong white bread flour (Doves Farm, Allinson, Marriage's, or Shipton Mill). Two feeds usually fixes it.

If none of these get you moving, we've written a whole dedicated guide — see the troubleshooter for a starter that won't bubble.

What if I forget?

What if I forget to feed my starter?

If you forget to feed your starter, it will not die overnight. A room-temperature starter survives 2–3 days without food; a fridge starter survives 2–3 weeks. Hooch — a grey or dark liquid on top — is the signal it's hungry, not a death sentence. Pour off most of the hooch, discard down to 20 g, and feed at 1:1:1. Within 24 hours, healthy bubbles return.

Do you have to discard?

Do I have to discard before feeding?

You have to remove most of the starter before each feed, but you do not have to throw it away. The "discard" is the spoonful you save in a separate jar in the fridge to use in pancakes, crackers or quick breads. Discarding keeps the new feed at a workable ratio — if you fed without removing any, the jar would double in size every day and the bacteria would outrun the yeast.

Going on holiday: the British two-week problem

We've all done it. The kit gets packed, the dog goes to the kennels, and the starter sits forgotten on the worktop. Here is the honest UK plan.

We don't recommend freezing as a first choice — it works, but the recovery is slower than from dried.

What's next

Once you've got the feeding rhythm, the next questions are usually "how long until I can actually bake with it?" and "why isn't mine bubbling like the photos?" Both have full guides — see how long until your starter is ready and the troubleshooter for a starter that won't bubble. And if you want the bigger picture — feeding, choosing a flour, troubleshooting and storage in one place — our complete UK guide to sourdough starters is the hub.

Frequently asked questions

How often should I feed my sourdough starter?

Feed once a day at room temperature, or once a week in the fridge. In a UK kitchen above 22°C in summer, twice a day for a few weeks won't hurt. If you bake less than once a fortnight, dehydrate a backup — it lasts years.

What is the 1:1:1 feeding ratio?

1:1:1 means equal weights of mature starter, flour and water. Keep 20 g of starter, add 20 g of strong white bread flour and 20 g of water, stir. That ratio peaks in around 8–12 hours in a typical UK kitchen and is the right default for almost everyone.

Can I use tap water to feed my starter?

In most of the UK, yes. Cold-tap water from the mains works well. If your water is heavily chlorinated (you'll smell it) leave it uncovered in a jug for 30 minutes before use, or use bottled still water. Hard water is generally fine — the minerals are food.

What flour is best for feeding a starter?

Strong white bread flour for daily feeds — it builds a clean, predictable starter. Once a week, swap in 20% wholemeal or rye for a kick of minerals and wild yeast. Avoid self-raising and chlorinated supermarket-own plain flour for daily feeds.

How do I feed a starter from the fridge?

Take it out, pour off any hooch, stir, discard down to 20 g, feed at 1:1:1, leave on the counter. Within 4–8 hours it should be domed. If it's slow on the first feed (normal after a long fridge stretch), feed it once more after it peaks and falls.

What if my starter smells like nail polish?

That's acetone — a starved-starter signal, not a sign it's broken. Discard down to 20 g, feed at 1:1:1, leave 12 hours, feed again. Two feeds usually restore the ripe-yoghurt smell. If three feeds in, nothing changes, switch to a wholemeal feed for a day.

Do I have to discard before every feed?

You have to remove most of the starter — otherwise the jar doubles in size every day and the bacteria overrun the yeast — but you don't have to bin it. Keep the discard in a separate fridge jar. It makes excellent pancakes, crackers and quick breads.

We're going on holiday for two weeks — what do we do with our starter?

Three options, in order of how relaxed we want you to be: (1) leave a labelled jar of flour with a neighbour and a one-line instruction; (2) dehydrate a backup a few days before you go (it keeps for years); (3) feed at 1:5:5, leave 4 hours, lid it loosely and put it at the back of the fridge — be ready to spend 2–3 days reviving it on your return.