Keeping a starter alive
A sourdough starter, shown rather than told
Feeding ratios sound like maths. They’re really about timing — when your starter will be ready. Have a play with it below.
The short version
If you read nothing else on this page, read these four.
- 1
Keep the jar in the fridge
You only need to feed it every 2–4 weeks. Daily feeding is for bakeries, not for you.
fine print
Cold slows the yeast right down. Many starters survive far longer than four weeks between feeds — this is a hardy thing, not a fragile one. - 2
A night or two before baking, feed it
Take some out, mix 1 part starter with 2 parts flour and 2 parts water, and leave it on the bench.
fine print
20g starter, 40g flour, 40g water is a good size. Discard the rest of the old starter, or save it for crackers. Discarding isn't waste — without it the jar grows huge and the yeast never gets enough fresh food. - 3
Wait for it to double
Bubbly, domed on top, about twice the level you fed it to. That's when it's strong enough to raise a loaf.
fine print
At room temperature that's roughly 6–8 hours. Mark the jar with a rubber band or a marker pen when you feed it, so you can actually see the rise rather than guessing. - 4
Use 100g, feed the rest, back in the fridge
That's the whole cycle. Repeat whenever you want to bake.
fine print
Keep 150–200g on hand when you're planning to bake, so there's enough to use and enough left over to keep going.
The cycle
Every feed goes through the same four stages
Your starter rises, peaks and sinks back down on repeat. Learning to read where it is in that cycle is most of the skill — the rest is just waiting.
Just fed
Thick, smooth and flat. Nothing happening yet.
Mark the level on the jar so you can see the rise.
Rising
Bubbles appear through the sides, and the top starts to lift.
Nothing to do. This is the yeast getting to work.
At its peak
Roughly doubled, domed on top, and full of bubbles.
Use it now — or refrigerate to hold it here.
Collapsed
Sunk back down with a flat or dipped top.
Still fine for crackers or pancakes. Feed it before baking bread.
Try it
How the feeding ratio changes the timing
More food takes longer to get through. That’s the whole idea behind ratios: you’re not making the starter stronger, you’re choosing when it will be ready. Pick a feed and watch the curve move.
The standard feed. Everyday maintenance, and overnight or fridge storage.
At 22°C a 1:2:2 feed peaks in about 8 hrs. Temperature moves this more than anything else you can control.
- Looks like
- Thick, smooth and flat. Nothing happening yet.
- Smells
- Milky, like raw dough.
- Do
- Mark the level on the jar so you can see the rise.
Why does more food mean a slower rise?
So which one should I use?
Peaked before you’re ready? Put it in the fridge.
This is the single most useful trick for fitting sourdough around a normal life. The cold holds the starter near its peak instead of letting it rise, exhaust itself and collapse on the bench while you’re out. You are not obliged to bake the moment it doubles.
Taking it back out
Want the full detail?
Troubleshooting, reviving a neglected jar, and the full doubling table.