How to store and maintain a sourdough starter

A sourdough starter is a living culture, and like anything living, it needs a degree of care to stay healthy. The good news is that care is simpler than most people expect — and a well-maintained starter will reward you with years of reliable baking.

Here's everything you need to know about storing and maintaining your sourdough starter, whether you're baking every week or just occasionally.

The two modes: counter and fridge

Your starter operates in one of two states depending on how often you bake.

Counter storage is for active bakers. If you're baking every one to three days, keep your starter at room temperature and feed it daily. At room temperature the fermentation cycle is fast — the starter will peak (double in height) and fall back within a few hours of feeding. You want to use it or feed it again at or just before peak activity.

Fridge storage is for everyone else. If you're baking once a week or less, the fridge is your friend. Cold temperatures slow fermentation dramatically, which means you only need to feed your starter once a week rather than daily. Take it out, feed it, let it sit at room temperature for a few hours, then put it back. It will stay healthy indefinitely on this schedule.

How to feed your starter

Feeding a starter means giving it fresh flour and water to consume. The wild yeast and bacteria in the culture digest the sugars in the flour and produce carbon dioxide and acids — the bubbles and tang that make sourdough what it is.

A basic feeding ratio is 1:1:1 — one part starter to one part flour to one part water by weight. So if you have 50g of starter, add 50g of flour and 50g of water, mix well, and leave it to ferment.

You can adjust this ratio depending on how quickly you want your starter to peak. A higher ratio of flour and water to starter (1:2:2 or 1:5:5) slows fermentation and is useful if you want to time your starter to peak overnight or while you're at work. A lower ratio speeds things up.

Bread flour (bakers flour) gives the best results — the higher protein content feeds the culture more effectively than plain flour. Wholemeal or rye flour can be added in small amounts to boost fermentation activity.

Signs of a healthy starter

A healthy starter doubles in height within 4–6 hours of feeding at room temperature, has visible bubbles throughout, smells pleasantly sour or tangy (think yoghurt or mild vinegar), and passes the float test — a small spoonful dropped in water will float when the starter is at peak activity.

The rise-and-fall cycle is the key thing to watch. Mark the level of your jar with a rubber band after feeding and check it a few hours later. A starter that reliably doubles and holds that height before falling is ready to bake with.

What to do with discard

Every time you feed your starter, you have a choice: keep all of it and add fresh flour and water on top, or discard some before feeding. Most bakers discard to keep the volume manageable — if you never discard, your starter grows exponentially and eventually you'd need a very large jar and a lot of flour.

Discard isn't waste. It's a slightly less active version of your starter that works beautifully in pancakes, waffles, crackers, flatbreads, and quick breads. Keep it in a separate container in the fridge and use it within a week or two. It has a more pronounced sour flavour than active starter, which adds depth to anything you bake with it.

Troubleshooting common problems

Liquid on top (hooch)

A layer of grey or dark liquid on top of your starter is called hooch — it's alcohol produced by the yeast and a sign your starter is hungry. It's not harmful. Pour it off or stir it back in, then feed as normal. If hooch is appearing frequently, try feeding more often or increasing the flour quantity slightly.

Starter smells very strong or unpleasant

A healthy starter smells sour, tangy, or slightly yeasty. A very strong acetone or nail polish remover smell usually means the starter needs feeding — give it a feed and it should recover within a day or two. A genuinely unpleasant or rotten smell (not just very sour) can indicate contamination; in that case, discard and start fresh.

Starter isn't rising after feeding

Check your kitchen temperature first — a starter in a cool kitchen (below 18°C) will ferment very slowly. Try moving it somewhere warmer. Also check your flour — old flour or flour with low protein content can produce sluggish starters. Switching to fresh bread flour usually helps.

Mould

Pink, orange, or black mould means discard and start again. Mould is rare with clean equipment and filtered water, but when it appears it can't be recovered from. Don't try to scoop it off and continue — the mould will have spread through the culture even if you can't see it.

Going on holiday

If you're away for more than a week or two, give your starter a good feed before you leave, put it in the fridge, and it will wait for you. For longer absences — months rather than weeks — the most reliable option is to dehydrate it. Spread a thin layer of active starter on baking paper, allow it to dry at room temperature for 24–48 hours, then crumble into flakes and store in an airtight container. It will keep for months and rehydrates just like Sourdough Flakes — because that's exactly what we did with Cintra when the family moved to Fiji.

How long does a starter last?

Indefinitely, with regular feeding. Sourdough starters have been passed down through families for generations — our own starter Cintra has been active for over a decade. A starter that's fed and cared for doesn't age in the way food ages; it simply matures, developing a more stable microbial community and a more complex flavour over time.

The oldest documented sourdough starters are over a century old. Yours, maintained well, could outlast you.

For more on getting started, see our full rehydration guide and FAQs. And if you're looking for what to bake next, our recipe inspiration guide has plenty of ideas beyond bread.