Why isn't my sourdough starter rising?
A sourdough starter that won’t rise is almost always one of four things: it is still young and building strength, your kitchen is too cold, the feed has too much old starter and not enough fresh flour, or the flour is low in nutrients. The good news is that all four are easy to fix, and a stalled starter is rarely dead.
Work through them in that order. They are listed by how often they turn out to be the cause.
Give a young starter time
A brand new starter often takes 10 to 14 days before it rises reliably. In the first week it may bubble, smell sharp, then go quiet. That is normal. Keep feeding it once or twice a day and watch for a consistent rise and fall between feeds before you judge it.
The quiet spell around days three to five catches almost everyone. Early bubbling is usually bacteria that will not survive the acidifying jar; the yeast that actually lifts your bread arrives later. If your starter bubbled hard on day three and has done nothing since, it is on schedule, not failing. Keep going and see how to make a sourdough starter for what each week should look like.
Warm it up
Temperature is the biggest lever on fermentation. A starter at 18C (64F) ferments far slower than one at 26C (79F). Move it somewhere warm: on top of the fridge, near the oven, or in the oven with just the light on. Aim for roughly 24 to 27C (75 to 81F).
Before you conclude it is not rising, check that you are not simply missing the peak. A cool starter can double and fall back overnight while you sleep, so you see a flat jar in the morning and assume nothing happened. Two ways to tell:
- Mark the level with a rubber band right after feeding, then check every couple of hours through a day.
- Look for a tide line. A ring of dried starter above the current level means it rose and fell without you.
If that is what is happening, the starter is healthy and only the timing is off. Feed at a larger ratio so the peak lands when you need it: sourdough feeding ratios explained.
Feed it more, with better flour
If you keep a lot of starter and add only a little flour, there is not enough fresh food to drive a strong rise. Try a larger feed ratio such as 1:5:5 (one part starter, five parts flour, five parts water). Adding a spoonful of whole wheat or rye flour helps too, since whole grains ferment faster and feed the culture well.
Carrying too much old starter forward has a second effect beyond food: it carries acid forward. A jar that is half old starter starts every cycle already acidic, and a low-pH environment favors the bacteria over the yeast. The result is a starter that smells sharp, bubbles, and never gains real lift. Three or four feeds at 1:5:5 usually resets it.
Bleached flour is worth ruling out as well. It works, but it is stripped of much of what a young culture needs. Unbleached bread flour, or an 80/20 mix of white and whole wheat, gives a struggling starter more to work with.
Check the water
Heavily chlorinated tap water can slow a starter down, especially a young one. If your water smells of chlorine, leave it uncovered overnight or use filtered water for a few feeds and see whether anything changes. This is a less common cause than the three above, which is why it is worth checking only once they are ruled out.
What a healthy rise looks like
After a feed, a strong starter rises, domes, and then falls back. The top of that rise is the peak, and it is the best time to bake. If you see bubbles throughout and a springy, mousse-like texture, it is working.
A useful benchmark: a healthy starter at 1:5:5 and 24C (75F) should roughly double in 10 to 12 hours, and hold near that peak for an hour or two before sinking. If yours doubles in four hours and collapses, it is not weak, it is fast, and it needs a bigger ratio or a cooler spot rather than more feeding. How to tell when your starter is ready covers the other signs.
When to worry
Throw a starter out only if you see fuzzy or colored mold, or it smells truly foul. A hungry starter that smells sharp, like acetone, is not spoiled. It just wants a feed.
Almost nothing else is fatal. Starters have been revived from a forgotten jar at the back of a fridge, from dried flakes years old, and from a layer of hooch and neglect. If you want a safety net for next time, dehydrate a spoonful while it is healthy and keep it in a drawer.
If the starter is fine but the bread still is not, work through the sourdough troubleshooting index instead: the problem is more likely fermentation time or shaping than the culture.