How to store a sourdough starter

To store a sourdough starter between bakes, feed it, let it begin to rise, then cover it and put it in the fridge. The cold slows fermentation to a crawl, so a starter that needs feeding every day at room temperature can sit for a week or more chilled. Refresh it weekly, and bring it back to room temperature before you mix.

Storing it in the fridge

The fridge is the right home for any starter you bake with less than daily. Feed it at your usual ratio, give it an hour or two at room temperature so the yeast wakes up, then chill it before it peaks. Storing it just after feeding means it keeps eating slowly in the cold instead of going hungry and sour.

A few practical points:

• Use a jar with a loose lid or one cracked open. Gas needs somewhere to go.
• Leave room. Even chilled, a starter can climb the jar over a few days.
• A dark liquid on top is hooch, a sign it is hungry. Pour it off or stir it in, then feed.

Cold storage sits around 4C (39F). That temperature is an estimate for a home fridge, and the door runs warmer than the back, so judge by how the starter looks rather than the clock.

The weekly refresh

A chilled starter is not dormant, just slow. Once a week, take it out, discard most of it, and feed the small amount that is left. This keeps the population fed and the acidity in check. If you skip a week now and then it will survive, but it gets sharper and weaker the longer it waits. See feeding your starter for ratios.

A 1:5:5 feed buys more time than a 1:1:1 feed, since there is more flour to work through. For fridge storage, the larger feed is usually the easier choice.

Reviving it before a bake

Pull the starter out a day ahead. It will be sluggish and flat, and it may smell strongly of alcohol. That is normal after a cold spell.

1. Discard down to about 20 g.
2. Feed it 1:5:5: 100 g flour, 100 g water, stirred smooth.
3. Leave it at room temperature, roughly 21C (70F).
4. When it has doubled and domed, feed it once more.

Two feeds is the usual rhythm, though a starter that has sat for weeks may want three. It is ready when it rises fast and predictably and passes a float test. Timings here are estimates. Judge the dough by feel, not by the hour. If you are dialing in a recipe afterward, the hydration calculator helps you keep the numbers straight.

Longer breaks

For breaks of a few weeks to a few months, you have two good options.

Break length	Best method	What to do
1-3 weeks	Fridge	Feed before storing, refresh once if you can
3 weeks to 2 months	Fridge, less attention	Expect a slow revival, two or three feeds
Months to indefinite	Dried	Spread thin, dry, store airtight

To dry a starter, spread a thin layer on parchment and let it air-dry until it cracks and flakes. Break it into shards and keep it in a sealed jar somewhere cool. To bring it back, crumble a spoonful into warm water, stir in flour, and feed daily until it is lively again. This can take three to five days, sometimes longer.

Dried starter keeps for a long time and travels well, which makes it a quiet insurance policy. Keep a small batch in a drawer and you can recover even if your jar in the fridge gets forgotten past saving.