How to Store Sourdough Starter in the Fridge

The best time to refrigerate a starter is after a feeding, while it is active and has fresh food available.

You can feed it at your usual ratio, such as 1:1:1 or 1:2:2. For example:

• 20 g mature starter
• 40 g water
• 40 g flour

Mix it well, scrape down the sides of the jar, and cover it loosely.

There is no need to wait until the starter reaches its highest peak before placing it in the refrigerator.
In fact, it is usually more practical to leave it at room temperature just long enough for fermentation to begin — often 30 minutes to an hour — and then refrigerate it.

This gives the yeasts and bacteria a chance to wake up and start working on the fresh flour. In the refrigerator, that activity continues slowly and the starter has food available for a longer time.

A starter can also be refrigerated right after feeding if your kitchen is very warm. It may ferment quickly on the counter and reach its peak before you are ready to use it.

Use a clean glass jar that gives the starter plenty of space to rise.

Even in the refrigerator, a healthy starter may expand noticeably during the first day. A jar that is too small can overflow, especially if you feed it at a high hydration or use rye or whole-wheat flour.

As a simple rule, the starter should fill no more than one-third of the jar after feeding. This leaves enough room if it doubles.

Do not seal the lid extremely tightly. A regular screw lid placed on loosely is usually fine. A small amount of gas can build up during fermentation, and the starter does not need to be under pressure.

Marking the level with a rubber band is useful. When you take the jar out later, the mark tells you whether the starter rose, peaked, and began to fall while it was cold.

For a healthy starter, one week in the refrigerator is easy. Many starters can stay there for two weeks without serious trouble, especially when they were fed well before storage.

After that, the starter may still be alive, but it is more likely to become acidic, thin, and less predictable. You may see a dark liquid on top, sometimes called hooch. It is simply a sign that the starter has used most of its food.

A starter that has been refrigerated for several weeks is not automatically ruined. It may only need a few room-temperature feedings to become strong again.

Still, regular care is kinder to the culture. If you are not baking, try to refresh your refrigerated starter about once every 7 to 14 days.

When it is time to refresh the starter, take the jar out of the refrigerator and look at it before feeding.
A slightly sour smell is normal. So is a little liquid on the surface, a flat appearance, or a few streaks on the side of the jar showing that it rose and later fell.

Discard most of the old starter, keeping a small amount — around 10 to 20 g is enough. Feed it with fresh flour and water, then leave it at room temperature until it becomes visibly active.

You do not always need to wait for a perfect full doubling before returning it to the refrigerator. But it should show signs of life: bubbles, a lighter texture, and some rise.

If the starter has been stored for only a week and looks healthy, one feeding is usually enough.

If it has been resting for much longer, give it two or three feedings at room temperature before baking. This helps reduce excess acidity and rebuild strong yeast activity.

A starter taken directly from the refrigerator is often cold, sleepy, and not yet at its strongest.

For reliable bread, remove a small portion and build a fresh levain or give the starter a room-temperature feeding. Use it when it has risen well, feels airy, and is close to its peak.

For example, if your recipe needs 100 g active starter, you can take 20 g from the refrigerator and feed it with 40 g water and 40 g flour. Once it has expanded and looks active, you have 100 g ready to mix into dough.

This method means you do not need to warm and feed the entire jar every time you bake. The main starter can remain small, clean, and easy to maintain.

If your starter normally takes four to six hours to peak at room temperature, plan your baking schedule around that time. A cold starter may need a little longer after its first feeding, particularly in a cool kitchen.

A layer of grey, brown, or dark liquid on the starter is usually not a reason to panic. It often appears when the starter has been stored too long or has run out of food.

You can pour it off if the smell is very sharp, or stir it in if you prefer. Then keep a small amount of starter and feed it generously.

The next feeding may smell better but still be slow. Give it another feeding once it rises. A healthy starter usually becomes fresher, milder, and more active with each refreshment.

However, do not use a starter that has visible fuzzy mould or unusual pink, orange, or red discoloration. In that case, it is safer to discard it completely and begin again with a clean culture.

Many bakers worry that refrigerating a starter will make it weak. A healthy starter can handle cold storage very well. The refrigerator simply changes the rhythm of feeding.

Instead of keeping the culture constantly at its peak, you give it a quiet pause between bakes. When you are ready to make bread again, one or two fresh room-temperature feedings bring it back into working condition.

A small starter, fed well and stored cold, is often easier to maintain than a large jar sitting on the counter. It creates less waste, fits a busy schedule, and still gives you everything you need for beautiful sourdough bread.

The goal is not to follow one strict timetable. Watch your starter. If it rises predictably after feeding, smells pleasantly tangy, and helps your dough ferment well, your fridge routine is working.