Sourdough Starter Troubleshooting

Dough Dough Guides

The question I get more than any other is a worried one: "Is my starter actually working?" Nine times out of ten the answer is yes — it's just doing its thing more quietly, or more slowly, than expected. Here's how to tell a healthy, active culture from one that genuinely needs help, and how to fix the handful of things that really do go wrong.

By Richard — I developed our shelf-stable starter myself and I keep cultures going every day for our Airbnb baking, so I've seen every wobble a starter can throw at you.

What an active, healthy starter looks like

Before you worry, check it against the real signs of life. A happy starter, at its peak a few hours after feeding:

The float test

Drop a teaspoon of starter into a glass of water. If it floats, it's full of gas and ready to bake with. If it sinks, give it more time or another feed. It's the quickest health check there is.

First thing to check: temperature

This is the answer far more often than people expect. Wild yeast is most active around 24–26°C. Below that it slows right down, and a cold kitchen can make a perfectly healthy starter look sluggish. My own kitchen sits at 22–23°C, so I know mine runs a touch slower and I give it time, or pop it somewhere warmer — near (not on) the oven, in a turned-off oven with the light on, or in an airing cupboard.

Symptom by symptom

"It's barely bubbling after a couple of hours"

Almost always just too cool. Move it somewhere warmer and give it more time — activity ramps up fast once it warms through. A barely-bubbling starter is rarely a dead one.

"No rise at all, even after feeding"

Three things to rule out: it's too cold (warm it up), the water was too hot and shocked it (start a fresh feed with lukewarm water), or it simply needs a couple more feeds to wake fully. Discard down to a small amount and feed it 1:1:1 (equal weights starter, flour, water) once or twice a day for 2–3 days — persistence almost always brings it back.

"There's a grey or brown liquid on top"

That's hooch, and it's harmless — just a sign the starter is hungry and due a feed. Stir it back in for a slightly tangier result, or pour it off, then feed as normal.

"It smells like nail polish, acetone or sharp vinegar"

An over-hungry starter. It has eaten everything and gone acidic. Feed it more often, or with a bigger ratio of flour and water (say 1:5:5), so it has more to live on between feeds.

"It smells sweet and doughy and won't rise"

Usually underfed or too cold. Feed it more generously and keep it warmer. A sweet, flat smell means the yeast isn't getting going.

"It rises beautifully, then collapses quickly"

Nothing's wrong — it simply peaked and ran out of food. Either use it sooner after feeding (catch it at the top of its rise) or feed a bigger ratio so it takes longer to peak and holds there.

"I forgot to feed it for weeks"

Don't panic — starters are tougher than they look. As long as there's no mould or pink, it's almost certainly revivable. Discard down to a tablespoon, feed 1:1:1, and repeat once or twice a day. Within 2–3 days it should be bubbling and doubling again. Full routine in my feeding & care guide.

When to actually worry

Only mould or pink/orange streaks. Everything else — slow bubbling, hooch, a sharp smell, a collapse — is normal starter behaviour and completely fixable with food and warmth. And if our starter genuinely never comes to life, that's exactly what the 2-hour activation guarantee is for: we'll replace it, no questions asked.