Sourdough starter feeding ratios
A feeding ratio is written as starter : flour : water, by weight. A 1:2:2 feed with 20 g of starter means 20 g starter, 40 g flour and 40 g water. The more fresh food relative to starter, the longer it takes to peak.
| Ratio | Example | Peak at about 24°C / 75°F | Good for |
|---|---|---|---|
| 1:1:1 | 30 g starter, 30 g flour, 30 g water | 3 to 5 hours | A quick feed, or a starter that needs a boost |
| 1:2:2 | 25 g starter, 50 g flour, 50 g water | 5 to 7 hours | Daily feeding, building a levain in the day |
| 1:5:5 | 10 g starter, 50 g flour, 50 g water | 8 to 12 hours | Overnight feeds, warm kitchens |
| 1:10:10 | 5 g starter, 50 g flour, 50 g water | 12 hours or more | Leaving it for a day in summer |
These times are typical for a mature starter. Yours may be faster or slower. Watch a few cycles and note how long it takes to peak at your usual ratio and temperature.
Starter hydration
Equal weights of flour and water make a 100% hydration starter, the standard on this site and in most recipes. It's easy to stir and easy to calculate. A stiff starter at 50 to 60% hydration ferments more slowly and tends toward a milder, more acetic tang; adjust the recipe water if you use one.
When to use your starter: catching the peak
Use starter or levain at or just before its peak, when it's well risen, domed and full of bubbles. Just past peak, when the dome begins to flatten, still works. Long past peak, when it has collapsed and smells sharp, the yeast are tired and the dough will rise slowly.
A fridge routine for weekly bakers
If you bake once a week or less, keep the starter in the fridge at 3 to 5°C (37 to 41°F). Cold slows fermentation enough that it only needs feeding about once a week.
- Feed it. Keep 20 to 30 g of starter and feed at 1:2:2 or 1:3:3.
- Give it a head start. Leave it at room temperature for 1 to 2 hours, until it shows the first bubbles.
- Refrigerate. Put the jar, loosely lidded, in the fridge.
- Before baking, take it out the day before. Give it one or two feeds at room temperature until it doubles reliably again, then build your levain.
A starter left for two or three weeks in the fridge usually survives. It may need two or three feeds at room temperature, ideally at 1:1:1, to bounce back.
Reviving a sluggish starter
- Warm it up. Move it somewhere at 24 to 27°C (75 to 80°F) and use warm water.
- Feed more often at a smaller ratio such as 1:1:1, twice a day, for two or three days.
- Add some wholegrain flour. A spoonful of rye or whole wheat in each feed often wakes a white-flour starter up.
- Check the flour. Some bleached flours ferment slowly. Unbleached flour is a safer choice.
Why you discard starter
Without discarding, the jar grows with every feed and the starter never gets enough fresh flour to stay strong. Keeping only a small amount makes feeds cheap and keeps the culture vigorous. Collect discard in a jar in the fridge and use it within about a week in crackers, pancakes and other recipes.
Drying starter as a backup
Spread a thin layer of ripe starter on baking paper and let it dry completely at room temperature, then crumble it into a clean, dry jar. Dried starter keeps for months. To revive it, soak a spoonful in water, add flour and feed daily as in the starter guide until it doubles reliably.
Feeding a sourdough starter: FAQ
How often should I feed a starter kept in the fridge?
About once a week at 3 to 5°C (37 to 41°F). Take it out the day before you bake and give it one or two feeds at room temperature.
What ratio should I use for an overnight feed?
1:5:5 peaks in about 8 to 12 hours at 24°C (75°F), which suits an overnight feed or a warm kitchen. Watch a few cycles, because your starter may be faster or slower.
I forgot my starter in the fridge for three weeks. Is it dead?
Usually not. A starter left for two or three weeks generally survives. Give it two or three feeds at room temperature, ideally at 1:1:1, and it should bounce back. Throw it out if you see mould or pink or orange streaks.