Why Is My Sourdough Starter Not Rising? (And How to Fix It)

Last updated on October 28th, 2025

A sourdough starter is essentially a living culture made up of flour, wild yeast, and beneficial bacteria. When everything’s working right, these tiny organisms throw themselves a feast every time you feed them, munching on the flour and producing carbon dioxide as they party. That gas gets trapped in the mixture, causing it to puff up and double in size—sometimes even triple if you’ve got a really vigorous culture going.

The magic happens through something called natural fermentation. Wild yeast and lactic acid bacteria consume the fresh flour you add, which increases their activity and population, producing carbon dioxide in the process. But if you’re wondering “why is my sourdough starter not rising,” most non-rising starters aren’t actually dead—they’re just dormant, underfed, or living in conditions that aren’t quite right for them to thrive.

Table of Contents

• Understanding the Rising Process
• Temperature Issues
• Feeding Ratios
• Flour Quality
• Water Quality
• Container and Environment
• Contamination or Dormancy
• Fixing and Reviving a Starter
• Your Starter's Ready to Shine
• FAQs – Why Is My Sourdough Starter Not Rising?

Understanding the Rising Process

Think of your sourdough starter as a tiny factory where yeast and bacteria convert the simple sugars in the flour into carbon dioxide, ethanol, and acids. That CO₂ is what actually lifts your starter from a flat pancake into a bubbly, doubled wonder. The carbon dioxide bubbles get trapped in the flour proteins, glutenin and gliadin, which form a gluten network when water’s added. Think of gluten like a stretchy balloon. When those yeast and bacteria start producing gas, the gluten network inflates and stretches to contain all those bubbles. The stronger and more developed that network, the better your starter can trap gas and rise.

A thriving starter doesn’t just sit there looking slightly puffy. When you feed a sourdough starter, yeast cells feed off the carbohydrates in the flour and turn them into carbon dioxide and ethanol through alcoholic fermentation. During this process, the yeast colony reproduces like crazy, and when your starter hits its peak, that colony’s at its largest and most active. You’ll know you’re watching a healthy rise when your starter doubles—sometimes even triples—in volume. It’ll be domed on top, covered in bubbles both large and small, with a pleasant tangy smell rather than anything harsh or off-putting.

Timing matters more than you’d think. Eventually, yeast and lactic acid bacteria consume all the sugars in the flour, and your starter hits its peak, then the bacteria start breaking down the gluten network, allowing the gas to escape. This is why your starter falls back down after reaching its height. If you catch it right at peak—when it’s doubled and just starting to think about deflating—that’s your golden window. Feed too early and you’re diluting a weak colony. Wait too long and you’re working with hungry, exhausted microbes.

Related: How Long To Let Sourdough Rise – Tips for Best Oven Spring

Temperature Issues

Why Temperature Is the Silent Killer

Let’s get real about temperature. Sourdough fermentation thrives at temperatures between 75°F-82°F, with fermentation still happening outside these ideal temperatures, just at different rates. Drop below that range and your yeast basically hits the snooze button. Push too high and they go into overdrive, then burn out fast.

I’ve seen people troubleshoot everything from their flour to their water to their feeding schedule, only to discover their kitchen’s sitting at a chilly 65°F. At cold temperatures of 68°F and below, fermentation will slow way down, take much longer to rise or not rise at all, and can lead to underproofed bread. Your starter’s not broken—it’s just cold.

Signs Your Starter’s Too Cold

A cold starter is sluggish. You’ll feed it and hours later… nothing. Maybe a few bubbles on top if you’re lucky, but no real lift. In colder temperatures, especially below 68°F, fermentation can take much longer—we’re talking 12 to 24 hours instead of the usual 4 to 8.

Sometimes you’ll see a clear liquid forming on top. That’s hooch, and while it’s not necessarily bad, it’s a sign your starter’s been sitting around waiting for something to happen while it slowly runs out of food.

When Things Get Too Toasty

On the flip side, temperatures at 90°F or above speed up fermentation, leading to overly sour flavor and dough that breaks down fast, with weak structure and gummy crumb. I’ve watched starters go from flat to peaked to collapsed in just a couple of hours when the kitchen got too warm.

If your starter reaches a temperature of 130°F, the yeast cells will die off. So if you’ve been keeping your starter in the oven with the light on and accidentally preheated without remembering it was there, you might need to start fresh.

Simple Fixes for Temperature Problems

For cold kitchens, try placing your starter in warmer spots. Moving your starter to a warm spot like above your fridge or near a radiator or vent can help, or you can use warm water between 80°F to 90°F instead of cool water when feeding. Some folks swear by keeping their starter in the oven with just the light on, or even in the microwave with a cup of hot water beside it (microwave off, obviously).

During those scorching summer months, find the coolest spot in your house—usually low to the ground, away from windows. You can even pop your starter in the fridge between feedings to slow things down.

Feeding Ratios

Understanding the 1:1:1 Baseline

When recipes talk about feeding ratios, they’re referring to the relationship between starter, flour, and water by weight. A 1:1:1 ratio means equal parts of each—say, 50 grams starter, 50 grams flour, 50 grams water. Simple enough, right?

But here’s where it gets tricky. Using too much discard can overwhelm the fresh ingredients, leading to an overly acidic environment that hinders yeast activity and the starter’s ability to rise. When you keep too much old starter and don’t add enough fresh food, it’s like inviting 50 people to dinner but only cooking for 10.

When to Use Higher Ratios

Overfeeding dilutes the yeast culture, while underfeeding can lead to a buildup of byproducts that inhibit yeast activity. Finding the sweet spot takes practice.

For a sluggish starter, try a 1:3:3 or even 1:5:5 ratio. This gives your microbes more food relative to their population, letting them rebuild their numbers. Putting 25 grams of starter in a jar and feeding it 50 grams of flour and 50 grams of water should help the starter double in size in about 12-24 hours.

Grab yourself a cheap digital scale—they’re like fifteen bucks—and suddenly your feedings become consistent and predictable. Flour settles differently depending on humidity and how it’s scooped, so weighing beats measuring cups every time.

Flour Quality

Not All Flour Is Created Equal

Here’s something that shocked me when I first started: the flour you choose genuinely matters. Adding whole-grain flour when feeding gives the natural yeasts and bacteria more nutrients to eat, which translates to a more robust rise. White all-purpose flour works, sure, but it’s like feeding your starter plain rice versus a nutritious meal.

The Whole Grain Advantage

Rye and whole wheat flour offer more nutrients, acting like a superfood for the bacteria and yeast to help the sourdough starter ferment and rise more vigorously. These flours contain more of the bran and germ, which is where wild yeast naturally lives.

Adding whole-grain flours like rye, whole wheat, or pumpernickel—about 10% to 20% by weight in proportion to white flour—when feeding will accelerate fermentation. You don’t have to go all-in on whole grain either. Even swapping a small portion can jumpstart a lazy starter.

Make sure your flour isn’t bleached, as this strips away the nutrients required to feed your wild yeast colony. Bleaching chemicals can also leave residues that inhibit fermentation. Organic flours tend to have more active wild yeast populations, too.

Related: How to Get Sourdough to Rise More: Top Tips for Every Stage of Baking

Water Quality

The Chlorine Problem

Let’s talk about what’s coming out of your tap. The key to sourdough starter success is using water without chlorine, which can cause the starter to die. Municipal water systems add chlorine to kill bacteria, which is great for public health, but not so great when you’re trying to cultivate bacteria for bread.

If you’re using unfiltered tap water in your sourdough starter and it’s not rising or forming bubbles, this may be the reason. Some cities use chlorine that dissipates quickly, while others use chloramine, which is way more persistent.

Quick Fixes for Tap Water

The easiest solution? You can use bottled water or simply filter your tap water for your sourdough. A basic Brita filter works fine. A Brita water filter jug will remove sufficient chlorine and other contaminants from your tap water to make it suitable to feed your sourdough starter.

No filter? You can leave a pitcher uncovered at room temperature for 24 hours to allow the water to off-gas and remove chlorine. Just remember, this only works for chlorine, not chloramine.

Distilled water is bad for sourdough because the process removes minerals that are important for your sourdough starter to thrive. Your yeast and bacteria need those trace minerals to function. Spring water or filtered tap water usually hits that sweet spot.

Container and Environment

Why Your Jar Choice Matters

Your container affects how well you can monitor and maintain your starter. Clear glass jars are ideal because you can see what’s happening on the sides. Always use clean utensils and glass or food-grade plastic containers with a loose-fitting lid.

Mason jars work beautifully. They’re wide enough to make stirring easy, tall enough to accommodate doubling, and the glass won’t react with the acids in your starter.

Your starter needs some airflow, but not so much that it dries out. I like to screw a metal lid on just barely enough to keep things from getting in, but not airtight. Some folks use a coffee filter secured with a rubber band. Both work.

Pick a jar that gives your starter room to double without overflowing. One game-changer: use a rubber band to mark where your starter sits right after feeding. Slide it to the top level, and you can instantly see when it’s doubled.

Keep your starter away from drafts and direct sunlight. Yeast and direct sunlight don’t mix well. If you’re using a sunny windowsill to keep things warm, put your jar in a box or cover it with a towel.

Contamination or Dormancy

How to Tell What You’re Dealing With

Not all starter problems are contamination, but when they are, you need to know. Bad bacteria may cause an unpleasant odor—smelling off or rotten instead of yeasty or like tangy yogurt—and may have pinkish liquid or visible mold on top. If you see actual mold, that starter’s done for.

But dormancy is way more common than contamination. If your starter has not risen and fallen, clear liquid on top is water separation, not hooch—only if the starter has risen and fallen is it hooch. A dormant starter just needs consistent feeding and time.

Common smells include nail polish remover, vinegar, beer, or even vomit-like odors, which are natural byproducts of the fermentation process. Rye flour, especially, can have a pungent aroma that’s off-putting but totally normal.

The only smell to worry about is mold—musty, obviously rotting, or like something died. Trust your instincts. If you’ve ever smelled moldy food, you’ll recognize it immediately.

Hooch is that dark liquid that forms on top of a hungry starter. It’s alcohol, and it’s harmless. Once your starter develops mold or signs of being overtaken by bad bacteria, indicated by an orange or pink tinge or streak, it’s time to start over.

If your starter has been kept on the counter for a few days or in the fridge for a couple of weeks without being fed, it will naturally become less active and essentially go to sleep once it has consumed all available food. This isn’t death—it’s just hibernation.

Fixing and Reviving a Starter

When your once-reliable starter starts acting up, sometimes it just needs a reset. Take 25 grams of sourdough starter and transfer it into a clean jar, then feed it 50 grams of water and 50 grams of flour. This 1:2:2 ratio gives your microbes plenty of fresh food relative to their population.

Cover the jar loosely, mark the top with a rubber band, and allow the starter to rise at room temperature until it doubles in size—this might take up to 24 hours. Once it finally doubles, repeat the process. The second feeding should show faster activity, potentially doubling in just 4 to 8 hours. That’s your sign that you’ve successfully reset things.

For a starter that’s been seriously neglected, here’s what works:

• Feed consistently twice daily using the same ratio at the same times
• Add whole-grain rye flour due to the increased nutrients present, keeping it warm and giving it timely feedings right when it’s ripe
• Keep temperature steady in that 75°F-82°F sweet spot
• Watch for improvement with each cycle—faster rising, more bubbles, better smell
• Mark your jar with a rubber band to track doubling accurately
• Be patient—revival can take a week or more of consistent care

Each feeding is like practice, strengthening that microbial community until it’s robust enough to leaven bread. Think of it like training for a race—you build up gradually, and your starter does the same.

If you’ve been feeding consistently for two weeks with zero improvement, no bubbles, no rise, and a persistently bad smell, starting fresh might be your best option. Making a new starter from scratch usually takes about a week.

Your Starter’s Ready to Shine

Most rising issues come down to temperature, feeding, or water quality—all easily fixable once you know what to look for. Your starter’s trying to communicate with you through its behavior, from sluggish rises to funky smells. Once you learn its language and give it the consistent care it craves, you’ll be rewarded with a bubbly, active culture that bakes beautiful loaves every single time. Keep experimenting, stay observant, and trust the process!

FAQs – Why Is My Sourdough Starter Not Rising?