Why Is My Sourdough Starter Bubbling But Not Rising And What To Do

If you’ve been nurturing a sourdough starter for days or even weeks, seeing bubbles might feel like progress—until you realize it’s not rising. Bubbling indicates microbial activity, but lack of rise suggests something’s missing in the equation. Many home bakers face this exact dilemma: their starter looks alive but fails to deliver the lift needed for a good loaf. The truth is, fermentation isn’t just about bubbles—it’s about strength, balance, and timing.

This issue often stems from subtle imbalances in temperature, feeding ratios, flour choice, or maturity. Understanding why your starter behaves this way—and how to correct it—is essential for achieving reliable results in sourdough baking.

What Bubbling Means (and What It Doesn’t)

Bubbles in a sourdough starter are a sign that wild yeast and lactic acid bacteria are consuming carbohydrates and producing carbon dioxide and organic acids. That’s fermentation in action. However, bubbling alone doesn’t mean your starter is ready to leaven bread.

A healthy, active starter should not only bubble but also visibly expand—ideally doubling in volume within 4–8 hours after feeding. If yours bubbles vigorously but remains flat, it may be producing gas without sufficient structural integrity to trap that gas. In other words, the gluten network in the mixture isn’t strong enough, or the yeast population isn’t robust enough to generate sustained lift.

“Bubbling shows life, but rising demonstrates strength. A starter must develop both metabolic activity and physical structure to perform well in dough.” — Dr. Karl De Smedt, Microbiologist at the Sourdough Institute

Common Causes of Poor Rise Despite Bubbling

Several factors can disrupt the delicate ecosystem of a sourdough starter. Here are the most frequent culprits:

1. Immature Starter

In the first few days of creation, a starter may bubble due to early-colonizing bacteria like *Leuconostoc*, which produce gas but aren’t effective at leavening. True bread-raising power comes when *Saccharomyces cerevisiae* and related strains dominate—typically around day 7–10 with consistent feedings.

2. Incorrect Feeding Ratio

Using too much water or too little flour can weaken the starter’s consistency. A runny starter lacks the viscosity needed to hold gas bubbles. Conversely, an overly stiff mix may restrict microbial movement.

Tip: Stick to a 1:1:1 ratio (starter:flour:water by weight) during maintenance, especially if your starter struggles to rise.

3. Wrong Flour Type

All-purpose flour works, but whole grain flours (especially rye or whole wheat) provide more nutrients and minerals that boost microbial growth. Relying solely on low-mineral white flour can slow development.

4. Temperature Fluctuations

Yeast and bacteria thrive between 70°F and 78°F (21°C–26°C). Cooler environments slow fermentation; excessive heat kills microbes. Drafty kitchens or seasonal changes can sabotage consistency.

5. Infrequent Feedings

Underfed starters become acidic and weak. Without regular refreshment, acetic and lactic acids accumulate, inhibiting yeast reproduction. This leads to bubbles from bacterial fermentation rather than yeast-driven expansion.

Step-by-Step Fix: Reviving a Bubbling but Non-Rising Starter

If your starter shows signs of life but won’t rise, follow this structured approach to rebuild its strength over 3–5 days:

1. Discard all but 20g of starter. Remove any hooch (dark liquid on top), as it signals hunger and acidity.
2. Feed with equal parts (by weight): 20g starter + 20g whole grain flour (rye or whole wheat) + 20g lukewarm water (about 75°F/24°C).
3. Mix thoroughly until smooth and no dry pockets remain.
4. Cover loosely and place in a warm spot (use a proofing box, oven with light on, or near a radiator if needed).
5. Repeat every 12 hours at consistent times (e.g., 8 AM and 8 PM).
6. After two days, switch back to all-purpose flour if desired, maintaining the same 1:1:1 ratio.
7. Observe closely: Look for doubling within 6–8 hours and a pleasant, yogurty aroma.

By day 3–4, you should notice increased volume and a domed surface. Once consistently doubling, your starter is ready for baking.

Do’s and Don’ts for Starter Health

Do’s	Don’ts
Use filtered or non-chlorinated water	Use chlorinated tap water (kills microbes)
Feed at consistent intervals	Feed irregularly or skip days
Keep starter in a clear jar for visibility	Store in opaque containers where activity is hard to track
Use kitchen scale for precise measurements	Rely on volume (cups/spoons)—inaccurate and inconsistent
Stir down before each feeding	Leave layers of dried crust unincorporated

Real Example: Sarah’s Week-Long Struggle

Sarah began her sourdough journey excitedly, mixing flour and water on day one. By day four, she saw bubbles and assumed success. But after five days, her starter still didn’t rise. She baked anyway—the loaf was dense and gummy.

She reviewed her process: using bleached all-purpose flour, feeding once daily with tap water, and storing the jar on a cold countertop. After switching to whole wheat flour, filtering her water, feeding twice daily, and placing the jar in a warmer cabinet, her starter doubled reliably by day nine. Her next loaf had an open crumb and proper oven spring.

Sarah’s case illustrates how small adjustments compound into dramatic improvements. No single fix worked alone—it was the combination of better nutrition, environment, and routine that made the difference.

When to Be Patient vs. When to Act

New starters take time. It’s normal for the first week to involve erratic behavior—foul smells, hooch formation, weak rise. This is part of the ecological succession where undesirable microbes give way to stable colonies.

However, if your starter has bubbled for over two weeks without rising, intervention is necessary. At that point, stagnation likely results from chronic underfeeding, poor flour quality, or suboptimal temperatures—not natural development.

“Think of your starter like a garden. You can’t expect roses if you never weed, water, or fertilize. Consistent care shapes the ecosystem.” — Ken Forkish, Artisan Baker and Author of *Flour Water Salt Yeast*

Troubleshooting Checklist

Use this checklist to diagnose and correct a non-rising starter:

• ✅ Is your starter fed at least once every 12 hours if kept at room temperature?
• ✅ Are you measuring ingredients by weight, not volume?
• ✅ Have you tried feeding with whole grain flour for a few cycles?
• ✅ Is your kitchen below 68°F (20°C)? Consider warming the environment.
• ✅ Does your water contain chlorine? Try filtered or bottled water.
• ✅ Is your container clean? Residual soap or oil can harm microbes.
• ✅ Are you discarding and refreshing regularly? Never let it sit unfed for more than 48 hours (at room temp).

Tip: Mark the starting level on your jar with a rubber band or tape. This makes it easy to see if your starter is truly doubling.

Frequently Asked Questions

Can I use my starter if it bubbles but doesn’t double?

Not reliably. While some rise may occur in dough, leavening will be weak and unpredictable. Continue feeding until it doubles consistently within 8 hours before baking.

How long does it take for a new starter to rise properly?

Most starters become fully functional between day 7 and day 14, depending on conditions. Cooler climates or infrequent feeding may extend this timeline.

Should I throw out my starter if it’s not rising after two weeks?

No. Most issues are reversible. Switch to whole rye flour, feed twice daily at 1:1:1 ratio, and keep it warm. Improvement is usually visible within 3–5 days.

Conclusion: From Bubbles to Lift—Building a Reliable Starter

A sourdough starter that bubbles but doesn’t rise isn’t broken—it’s communicating. It tells you it needs better food, warmth, or consistency. With attention to feeding ratios, flour quality, and environment, nearly every struggling starter can be revived.

The journey to a strong, predictable starter isn’t about perfection from day one. It’s about observation, adjustment, and persistence. Every failed rise teaches you more about the living culture in your jar. And once you achieve that confident double in volume—smooth, domed, and full of fine bubbles—you’ll know you’ve built something truly powerful.

💬 Have you revived a stubborn starter? Share your story or tip in the comments—your experience could help another baker succeed!