Sourdough Starter Not Rising: 6 Causes and the Fix That Works

An active sourdough starter should double in volume 4–8 hours after feeding. When your sourdough starter is not rising, the worst thing you can do is panic — a flat starter is one of the most common, most fixable problems in sourdough baking.

The short version

Work through the causes in this order, because each one is more common than the next:

1. Too cold. Sourdough microbes stop working below about 65°F (18°C). Most kitchen counters are colder than you think. A cup of just-boiled water next to the jar is enough.
2. Feeding ratio too large. A 1:1:1 feeding (starter:flour:water by weight) doubles reliably. A 1:5:5 feeding for a young starter floods the microbes with food they can't process.
3. Too watery. A thin, pancake-batter starter bubbles but can't trap gas, so it never visibly rises. Keep a stiff, thick paste consistency.
4. Chlorinated water. Tap water chlorine kills or stuns the bacteria. Leave water out overnight or use filtered water.
5. Wrong flour. Bleached all-purpose flour ferments noticeably slower than unbleached flour, whole wheat, or rye.
6. Not enough time. A starter that was recently refrigerated, diluted, or restarted can take 3–5 days to recover. Expect that, don't fight it.

Why a "dead" starter is almost never dead

Real sourdough starter death requires something extreme: sustained direct heat, bleach, or weeks abandoned in a sealed container. A starter that looks lifeless is usually dormant, not dead. Surface hooch, a sour, vinegar smell, and a layer of grey water all mean the microbes are alive and hungry — they're fermenting so fast they've exhausted their food.

Temperature first

Every sourdough problem can be traced to temperature, so check it before anything else. An active starter fed at 1:1:1 needs approximately:

If your kitchen is cool, put the jar on top of the fridge, next to the router, or inside the oven with only the oven light on (never a hot oven). A consistent 75°F (24°C) spot will fix more flat starters than any other change.

The feeding ratio rescue plan

If temperature isn't the problem, switch to a 1:1:1 maintenance feeding for three days:

• 20 g starter + 20 g flour + 20 g water (by weight)
• Same time every day, at warm room temperature
• Stir until thick and paste-like — add the water slowly; you want dough texture, not batter

Most starters that "stopped working" after a few weeks were slowly diluted by larger and larger feedings. Cutting the feed back to 1:1:1 re-concentrates the microbial population, and the rise returns within a feeding or two.

The schedule a young or stalled starter needs

When a starter is actually dead

You can trust your senses: an active starter smells pleasantly sour, like yogurt. A dead or badly infected starter smells putrid, like rotting food, or develops pink, orange, or green patches — that's mold, not hooch. If you see colored fuzz or smell decay, discard the jar and start fresh. One glowing exception: black liquid on top is fine — it's hooch (alcohol), a sign of over-hunger, and it rinses off with your next feeding.

What you'll see when the fix works

Within 24 hours of fixing temperature and feeding, expect a predictable rhythm:

1. Feeding morning: thick paste, lively smell
2. 3–5 hours: bubbles, dome forming at the surface
3. 6–8 hours: volume doubled, surface slightly domed
4. Peak: still bubbly, not collapsed — this is bake-ready starter