Why Is My Sourdough Starter Not Rising and What Can I Do?
A sourdough starter that stops rising is usually not dead—it is out of balance. The most common causes are underfeeding, cool room temperature, chlorinated or overly filtered water, and switching flour types too abruptly. In most cases you can revive it within three to seven days by discarding most of the starter, feeding it at a consistent ratio by weight, keeping it between roughly 75–80°F (24–27°C), and waiting for it to double before feeding again. Liquid on top (often called "hooch") is a sign of hunger, not death. Only discard and start over if the starter shows fuzzy mold, pink or orange streaks, or a persistently rotten smell that does not improve after several feedings.
First, Diagnose What You Are Actually Seeing
Before changing anything, separate normal behavior from real problems.
Normal signs
- Clear to dark liquid on top: This is alcohol and water produced as yeast exhausts its food. It means the starter is hungry, not dead.
- A thin, watery layer with a sharp, beer-like or vinegar smell: Also hunger. Stir it back in or pour it off, then feed.
- Little to no rise but bubbles throughout: The culture is alive but weak or cold.
- A burst of rise followed by a collapse: The starter peaked and ran out of food before you used it.
Warning signs
- Fuzzy mold on the surface or sides (green, black, blue, white fuzz rather than a flat white film).
- Pink, orange, or red streaks anywhere in the starter.
- A smell like nail polish remover, rot, or sewage that persists after two or three regular feedings.
- No bubbles at all after 48 hours at warm room temperature with fresh flour.
If you see mold or colored streaks, discard the starter and sanitize the jar. Do not try to salvage it.
The Main Reasons a Starter Stalls
| Cause | What you will notice | Fix |
|---|---|---|
| Underfeeding | Liquid layer, vinegar smell, flat texture | Feed more often or at a higher ratio |
| Too cold | Slow or no rise, bubbles but no expansion | Move to a warmer spot, 75–80°F |
| Too hot | Rise then sudden collapse, sour smell | Move away from heat sources above 85°F |
| Chlorinated water | Slow activity after water change | Use filtered or bottled water, or let tap water sit out |
| Bleached or old flour | Weak rise, pale color | Switch to unbleached bread or whole wheat flour |
| Abrupt flour change | Temporary stall for 1–3 feedings | Transition gradually over several feedings |
| Ratio too thin | Fast rise, quick collapse, watery | Feed by weight, not volume; aim for a thick batter |
| Ratio too stiff | Very slow rise, dry surface | Add slightly more water |
Step-by-Step Revival Plan
This schedule assumes a starter kept at room temperature. If yours lives in the fridge, take it out and let it come to room temperature first.
Day 1: Reset the ratio
- Discard all but 20 g of starter. If you have very little, keep whatever you have up to 20 g.
- Add 20 g unbleached all-purpose or bread flour and 20 g water. This is a 1:1:1 feed by weight.
- Stir well, scrape down the sides, and cover loosely.
- Leave at 75–80°F for 12 hours.
Day 2: Watch for a rise
- If it doubled within 4–8 hours, it is active. Feed again at 1:1:1 and repeat.
- If it rose only slightly, keep the 1:1:1 ratio but feed every 12 hours.
- If nothing happened, move it somewhere warmer and check your water and flour.
Days 3–7: Build strength
Once you see a consistent rise, increase the feeding ratio to 1:2:2 or 1:5:5 (starter:flour:water). A higher ratio gives the yeast more food and produces a more predictable peak. Feed when the starter has peaked and just begun to fall, not on a fixed clock.
A simple rule: feed at the same time each day, but adjust the ratio so the starter peaks about an hour before you plan to feed again.
How to Tell When It Is Ready to Bake
A starter is ready when:
- It doubles in volume within 4–8 hours of feeding at 75–80°F.
- The surface is domed, not flat or sunken.
- It smells mildly sour, yeasty, and slightly sweet—not sharply acidic.
- A small spoonful floats in water (a useful but not foolproof test).
- It has a web-like, stretchy texture when stirred.
If it only bubbles but never expands, it is not ready. Keep feeding.
Adjusting to a Home Baking Routine
You do not need to feed a starter every day if you are not baking every day.
- Baking weekly: Keep the starter in the fridge. Take it out the night before, feed 1:1:1, and let it sit overnight. Feed again in the morning before mixing dough.
- Baking daily: Keep it at room temperature and feed once or twice a day at 1:2:2 or higher.
- Baking rarely: Store in the fridge and feed once every one to two weeks. Pour off any liquid, discard most of the starter, and feed 1:1:1 before returning it to the fridge.
For a home baker who bakes once a week, a 50 g starter, 100 g flour, 100 g water maintenance feed is a practical size. It gives you enough to bake with and enough to keep the culture going without wasting flour.
When to Start Over
Start over if:
- You see mold or pink/orange streaks.
- The starter has been neglected for months and shows no activity after five days of consistent warm feeding.
- The smell remains genuinely rotten after multiple feedings.
Starting over is not a failure. A new starter made with whole wheat or rye flour often becomes active within five to seven days.
A Note on Expectations
A revived starter may take several days to return to full strength. Do not judge it by a single feeding. Judge it by the trend: more bubbles, faster rise, better smell. If the trend is improving, keep going. If nothing changes after a week of correct feeding, change one variable at a time—water, flour, or temperature—rather than all three at once.