How to feed a sourdough starter
To feed a sourdough starter, keep a small amount and refresh it with fresh flour and water in a set ratio. A common feed is 1:5:5, meaning one part starter to five parts flour to five parts water by weight. Stir until smooth, cover loosely, and let it rise until it roughly doubles. That is when it is at its strongest and ready to bake with.
What you need
- A scale. Feeding by volume is the single most common reason a starter behaves unpredictably, because flour packs and water does not.
- A jar with room to triple. A 500 ml jar for a 20 g starter is about right. Straight sides make the rise easy to read.
- Flour. Bread flour or all-purpose for everyday feeding, with a spoonful of whole wheat or rye if the starter needs a push.
- Water at room temperature. If your tap water is heavily chlorinated, leave it out overnight or use filtered.
The steps
- Discard down to what you are keeping. For a 20 g starter, spoon 20 g into a clean jar and set the rest aside as discard. Working in a clean jar each time keeps dried crust out of the mix.
- Add flour and water in your ratio. At 1:5:5 that is 100 g of flour and 100 g of water onto the 20 g you kept.
- Stir until no dry flour remains. Scrape the sides down so nothing dries onto the glass.
- Mark the level. A rubber band or a marker line on the jar turns “did it rise?” into a measurement.
- Cover loosely and leave it somewhere warm. Gas needs to escape, so a lid resting on top beats a sealed one.
- Wait for the peak. Risen, domed, bubbly through the middle, just before it starts to sink.
The feeding-ratio calculator works out the grams for any ratio and any amount you are keeping.
Pick a ratio
The ratio sets how fast the starter ferments. A 1:1:1 feed is small and fast and suits a warm kitchen or frequent baking. A 1:5:5 feed is larger and slower and gives you a longer window before the next feed. Both keep the starter at the same hydration if the flour and water parts are equal.
| Ratio | Peak at 24C (75F) | Use it when |
|---|---|---|
| 1:1:1 | 4-6 hours | Baking later the same day |
| 1:2:2 | 6-8 hours | Once-a-day feeding |
| 1:5:5 | 10-12 hours | Feeding at night to bake in the morning |
| 1:10:10 | 14-18 hours | Reviving a neglected starter |
The full comparison, and why 1:1:1 is not automatically the right default: sourdough feeding ratios explained.
How often to feed
Temperature decides this, not the calendar. The same starter at the same ratio peaks in about 4 hours at 28C (82F) and takes 12 or more at 18C (64F).
- Warm kitchen, 26-28C (79-82F). Twice a day, or once at a bigger ratio.
- Average room, 21-24C (70-75F). Once a day.
- Cool room, 18-20C (64-68F). Once a day, and expect a late peak.
- Fridge, 4-6C (39-43F). Once a week.
More detail per band: sourdough starter feeding schedule by temperature.
Watch for the peak
A healthy starter rises, domes, and then falls. The peak is the best moment to bake. If you are not baking yet, feed it again or refrigerate to slow it down.
The signs it has peaked: it has roughly doubled from your mark, the surface is domed rather than flat, bubbles run through the whole jar rather than just the top, and it smells tangy and faintly sweet. Once the dome dimples and starts to sink, it is past peak: still usable, but weaker, and your bulk ferment will run longer than you planned. How to tell when your starter is ready covers the float test and the other cues.
Storing it between bakes
To keep a starter you bake with weekly, feed it and put it in the fridge. Refresh it once a week. Before your next bake, take it out and feed it once or twice at room temperature so it is active and at its peak when you mix.
Fridge starters develop a layer of gray liquid on top called hooch. That is a hunger signal, not spoilage. Pour it off or stir it in, then feed as normal. Full details: how to store a sourdough starter.
What about discard?
The starter you remove before a feed is called discard. It is not waste. Use it in pancakes, crackers, or quick breads where you do not need a strong rise.
You can also feed less of it. Keeping 20 g instead of 100 g means a fifth of the flour and almost no discard at all, while still giving you plenty to build from before a bake.
If the feed does not take
A starter that stays flat after a feed is usually young, cold, underfed, or on flour too refined to sustain it. All four are fixable and none of them mean it is dead: why isn’t my sourdough starter rising.
The habit that matters most is regularity. A starter fed at roughly the same time each day settles into a rhythm you can predict, which is what makes it possible to plan a bake around it at all.
Everything else about keeping a culture, in one place: the complete sourdough starter guide.