How to Fix Overfed Sourdough Starter

The pandemic and lockdown sent millions of people into their homes to twiddle their thumbs. So of course, we found things to do. One of those things was baking bread, and sourdough was at the top of that bread list.

Sourdough can be tricky for many reasons, and much of it has to do with the yeast. Questions abound about how to get it just right. Where do you get the best starter? Can you make your own starter? Can you spoil a sourdough starter? How do you fix an overfed sourdough starter? And so much more.

Well, it’s best if we begin at the beginning.


In the beginning, bread was flat.

It’s true. All breads were flat and firm and resembled tortillas, pita bread, or, in the Hebrew tradition, Matzah.

These breads are called “unleavened.”

Unleavened bread is any bread that is made without rising agents like yeast and it was the only kind of bread people had access to for centuries.

People would grind grain, mix it with water, and bake it in stone ovens or over open fire. Tortillas and crepes are cooked directly on a flat heated pan.

Then, likely by accident, someone left their bread out too long, and it attracted some wild bacteria and yeast. Because yeast and bacteria are literally everywhere at all times, looking for some action.

Before they knew what was happening, the bread rose.


Well, that’s what yeast does. Yeast gets into a food or beverage and consumes the sugars and starches and converts them to alcohol and carbon dioxide, along with myriad other chemical compounds and micronutrients.

In bread, the carbon dioxide is trapped inside the dough, so instead of bubbles you get expanded, or “rising” bread.

Well, whoever came upon the risen bread was obviously not going to waste it. They threw it in the oven, and lo and behold, the first sourdough was born.

A lighter, tastier version of what would have been unleavened bread.

Sourdough Starter

From that point on, much like with beer and wine, the “starters” for sourdough were saved and used again for the next batch, and the next and the next, never to return to unleavened bread.

A sourdough starter, much like a yeast starter in beer or wine, is already fermented flour and water. It is basically a small batch of unbaked sourdough. It is a living organism that requires cultivation and maintenance. When fed well, you can keep a sourdough starter alive for years and make infinite loaves of sourdough bread.

Indeed, traveling pioneers in early America used to carry sourdough starter in their backpacks so they could stop and make bread around a campfire without having to find a town.

Test Your Yeast


A sourdough starter gets better with age. Expect it to be acidic, and add a light, airy, and chewy texture to your bread.

What’s the difference between sourdough starter and regular BAKER’S YEAST?

In short – the bacteria.

Instant yeast, active dry yeast, and fresh yeast are all just yeast, which is great on its own of course, but sourdough starter brings in wild yeast and wild bacteria, which add flavor complexity, that sour flavor we are all so fond of, and a ton of nutritional value as well.

Sourdough starter contains high volumes of folate, antioxidants, and lower phytate levels than regular bread, which help the body absorb the nutrients. It’s like having yogurt as bread.

To make your own sourdough starter, you need whole grain flower, water, and a non-reactive container like clear glass.

Whole grain flour naturally contains wild yeast. Your water should be close to 70 degrees Fahrenheit to welcome friendly bacteria and wild yeast. And your clear glass container is necessary so your sourdough starter won’t get contaminated in cracks and scratches, and so you can see its progress.

The process is simple: you’ll combine your flour and water and let it sit overnight lightly covered in your container.

The dough automatically begins fermenting and turning into sourdough starter.

Over the next several days, you will continue to feed your sourdough starter with more flour and water, checking to be sure it is bubbling and rising.

You will know it is “ripe” when it doubles in size 6 hours after being fed.

Overfed Sourdough Starter

Now, sometimes, and it happens to the best of us, a sourdough starter can “get sick.”

Overfeeding can be a cause of this “sickness,” as can lack of feeding and neglect.

Because, yes, you can overfeed your sourdough. The explanation is quite simple: if you add too much water and flour, you’re basically diluting the natural population of yeast and bacteria. This means that your sourdough starter will not rise much and will not be very bubbly. You’re basically back to an underdeveloped sourdough starter. In which case, you should probably just wait until the population of yeast and bacteria grows back to a healthy number and your sourdough starter acts like itself once again.

If you think you have sick sourdough starter, you can usually tell because:

  • It smells funny.
  • Has crust on top.
  • It has liquid sitting on top of goop.
  • Your sourdough starter is covered in mold.

Again, if you suspect you have overfed your sourdough starter, it is easy to remedy this problem. Most problems of sourdough sickness, in fact, can be remedied.

If you have a crust, remove it.

If you have liquid, you have made an alcoholic “hooch.” Simply pour it off and feed your sourdough starter as you normally would. Or you can simply mix it back in.

If your dough has a funny smell, it is probably underfed, which will require several feedings and close attention to bring it back into balance.

To reinvigorate a “sick” sourdough starter, simply add a little warm water and stir the starter throughout; you can even break it up with your fingers. Then add flour one cup at a time to thicken it up, until you get a soft dough and clumps together.

Knead your dough a bit to expel excess acid, and put it back in your clear container.

Then, continue on with your daily feeding until it is ready.

Remember, like with any food or beverage, you will need to experiment and play with various recipes you may find, different forms of wheat flour or even a barley or rye, and keep an eye on your starter as it develops.

Yeast starter analysis for professional bakers

Now, all this testing by smell, look and feel is fine if you’re a home baker. However, if you have a bakery and you’re aiming at obtaining great results every time, you might want to consider starting doing yeast cell counts and finding, in general, a more professional way to monitor your yeast. Because, after all, it is the single most important variable in your recipes.

Yeast cell counting is essential for bakers, particularly if you’re working with sourdough. And here are a few reasons why, besides avoiding under or overfeeding your starter:

For yeast starter maintenance

This is directly related to the discussion in this article. As already mentioned, the symbiotic culture of yeast and bacteria mixed with flour and water make up the starter that sourdough bakers use as a natural leavening agent. It is what provides the distinct flavor and rise to sourdough bread.

By doing cell counts and monitoring your yeast’s viability (which tells you exactly how much of your yeast is alive) you can keep your starter in perfect health. A decrease in cell counts and viability can immediately let you know that there’s something wrong – such as the temperature, maybe the presence of contaminants, stressed yeast, or any imbalance that can lead to off-flavors or poor dough rising.

For fermentation control

Only by knowing the exact state of your yeast you can adjust the fermentation conditions and only by finding the right fermentation conditions you can achieve the desired flavor, texture, and volume for your bread. Also, knowing your yeast count and how much of your yeast is alive allows you to use the ideal amount of yeast every time, which, as you well know, is crucial.

For consistency and reproducibility

If you’re baking at home, these are of little importance. You can bake a different bread every time and your family may still love it. However, if you’re a professional baker, your customer will expect not only quality but also consistency. By monitoring your yeast you can accurately estimate the fermentation time, dough development, and rise of your bread.

For problem-solving

Yeast monitoring helps you identify the issues that may arise during the bread-making process – it may help you understand why your bread isn’t rising properly or why it exhibits unusual flavors. A low yeast count may be associated with insufficient yeast activity (for various potential reasons), while a high yeast count might suggest overfermentation or even contamination issues.

Experimentation and recipe optimization

Yeast monitoring allows you to optimize your recipes. Once you have a complete understanding of your yeast, you can start manipulating it in order to fine-tune the characteristics of your bread, such as texture, crumb structure, flavor, etc. Adding more yeast (so a higher yeast cell count) may result in a more airy bread, while a lower count will probably lead to a denser texture.

Last but not least, whether you’re a home baker or a professional baker, don’t forget to have fun, and make sure to share with friends.


Passionate about yeast fermentation and all the wonders it can do? So are we! If you’re interested in finding out how you can use our technology to control fermentation and monitor your yeast, save work hours and improve the cost-efficiency of your business, drop us a line at [email protected]

Also, check out these product pages (keep in mind that while these were tailored to the needs or brewers and vintners, they work great for bakers as well):

or request a fully functional demo account to try our yeast analysis Web App.


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