Sourdough starter looking weak, or maybe even a little (gasp!) moldy? Don’t panic! Here’s how to revive a weak sourdough starter and get it back in shape with a little time and TLC.
I pulled my sourdough starter out of the refrigerator, took the lid off the jar, and paused. I knew right away something wasn’t right.
Wimpy and deflated, it didn’t have any of the bubbles that signify a healthy starter. It smelled funky instead of pleasantly sour. And what was that white film hovering on top?
Rather than begin a new starter and wait days to bake again, I determined to save this one if I could.
Within a day, I had a healthy sourdough starter again. It wasn’t hard to do, so if you need to revive a weak sourdough starter, here’s how.
Why A Starter Goes Bad
For months before the sickly starter fiasco, my sourdough starter lived a happy life in the door of my refrigerator. I’d pull it out every week or so, bake up a big batch of something yummy, then return it to its home after a meal of fresh flour and water.
But life happened and I left my hungry starter sleeping in the fridge too long. That’s usually the story when a starter goes bad.
Sourdough starters can last for decades as long as they get enough fresh flour and water. The flour you stir into your starter is food for the good microbes that ferment it. So as the microbes digest the flour, they need you to add more food so they don’t eventually starve.
If you keep the starter in a warm place, even at room temperature, the microbes gobble up the flour even faster.
Once the good microbes in your starter run out of food, they start to die off. Then the bad guys take over and you end up with a flat, moldy, and funky sludge.
Can You Still Use a Moldy Sourdough Starter?
Now I realize that anyone whose kitchen mantra is When in doubt, throw it out might have just suffered heart trauma because I was determined to save my starter. My starter that was growing some mold. That one.
We don’t save things with mold. We almost always throw them away, and quickly.
But a little mold on the top of a starter isn’t a necessary death sentence. You just need to send those sourdough starter microbes to the ICU, and stat. With enough fresh flour and water, you might be able to get the sourdough starters back in balance.
Microbes are an amazingly resilient bunch of critters. So if you’re looking at a starter with a little bit of mold floating on top, don’t panic. It’s likely savable.
However, if you’ve got mold growing through the entire starter and all over the container that stores it? It’s too far gone. You need to make a fresh sourdough starter.
Sourdough Starter Rescue: Step by Step
When you need to revive a weak sourdough starter, you have a few important goals.
- Remove the mold layer from the sad starter as thoroughly as possible.
- Completely clean your sourdough jar (or whatever container you use to store your finished starter).
- Get the sourdough microbes happy again with fresh flour, water, and a little air circulation.
Here’s how to do that, step-by-step.
Step 1: De-Mold
Pour off or spoon out the moldy layer. It’s not crucial to remove every trace of mold, but it’s best to get out as much as possible. Once your starter has fresh flour and water, the beneficial microbes will overtake any remaining mold.
Step 2: Transfer
Pour out the remaining starter from the jar into a clean measuring cup or bowl. It’s best not to scrape the sides of the jar when you do this so that you don’t add more moldy bits to the surviving starter you have, but you can scrape the bottom if you need to.
Step 3: Wash
Thoroughly wash the sourdough starter container to remove any other bits of mold with hot soapy water. Don’t worry about any dried starter that doesn’t want to wash off the sides. If you want to scrub and sanitize the jar until it’s spotless and disinfected, you can. I didn’t.
Step 4: Feed
At this point, you need to feed the remaining starter with fresh flour and water. If you have about 1/2 cup of starter left, you can give it 1 cup flour and enough water to bring it to the consistency you like. You can leave the starter in the bowl or measuring cup you poured it into for this part, or you can put it back in its now-clean jar.
Step 5: Air
Leave it out to ferment, lightly covered with cheesecloth or a thin kitchen towel, for around 6 hours. Overnight would probably work in a pinch. If you can leave it by an open window, that’s ideal since the extra airflow will bring in friendly microbes. If not, any room with airflow will be fine. Ideally, you’ll start to see some fermentation bubbles after this step.
Step 6: Repeat
Repeat the same process with another cup of flour and sufficient water. Leave it out for another 4-6 hours to get those microbes active and happy again. If your starter is salvageable, you should see bubbles all the way through it again after this.
If your starter just looks like a thin paste with no bubbles or other signs of fermentation, you probably need to make a fresh homemade sourdough starter.
Once your starter is bubbly again, consider it as good as new! You can use it just like you would have before it needed rehabilitation.
How to Keep a Starter Happy
It’s a good idea to figure out why your starter molded or got really weak so it doesn’t happen again.
In my case, I was storing it in the door of the fridge (which is the warmest area of it), so I needed to feed it more often than I was. I also wasn’t baking for weeks at a time, so I also wasn’t removing much of the old starter and replacing it with fresh flour and water.
Lesson learned: keep your starter in the back of the fridge if you’re going to take a break from regular baking. Pull it out every two weeks, discard half of the old starter, and replace it with fresh flour and water.
Remember, a healthy sourdough starter comes down to one important need: food. Give those microbes enough fresh flour and they’ll keep your starter bubbly and mold-free indefinitely.
But if you do let a sourdough starter get a little weak and sickly, you don’t have to despair. Follow these steps so your starter can once again smell pleasantly sour, look perky and bubbly, and live in the fridge without a trace of mold.
Delicious Sourdough Recipes You’ll Love
And now that you have a healthy starter again, it’s time to bake! Here are some yummy recipes to get you started:
- Simple Whole Wheat Sourdough Sandwich Bread
- Healthy Whole Grain Sourdough Morning Glory Muffins
- Easy Sourdough Drop Biscuits
- Irresistible Whole Wheat Sourdough Cinnamon Rolls
- The 50+ Best Sourdough Recipes That Will Have You Baking Tonight