Healthy Sourdough Starter

Ever take a ferment, of any kind, out of the fridge and smell a kind of funk? Or taken a sip or taste and wondered what went wrong? If you are unsure if your sourdough starter is safe, this is the post for you. Abigail gives you all the things to look for to determine if you have a healthy sourdough starter.

One of the most daunting parts of baking homemade sourdough bread is making and maintaining your own starter. It’s not that it’s a difficult process—feeding a starter simply consists of using most of the old starter and stirring in new flour and water. The most challenging part of cultivating a starter is telling when it’s healthy!

What Characterizes a Healthy Sourdough Starter?

Examine these characteristics to determine whether or not your sourdough starter is healthy.

Smell. A healthy sourdough starter will have a fruity, tangy pungency to it. Think of a smell similar to beer, only with the tang of active fermentation. If your sourdough starter smells gross, off, or stinky, it might be cultivating in a bad way.

Bubbles. An active sourdough starter will be bubbling—sometimes with visible motion! This is normal, and a good sign that the wild yeasts are doing their job, eating and “burping” away. That’s what will give your sourdough a beautiful airy texture.

What if your starter isn’t bubbling? Never fear. Chances are it just needs some reviving. Feed it some fresh water and flour, stir it in, and let it sit in a warm place. You’ll most likely see some bubbling action beginning after a couple of hours.

Liquid. A starter that sits stagnant in the refrigerator for some time will develop a layer of brownish-grey liquid that floats at the top of the jar. This liquid is not harmful and may be stirred back in, or poured off as needed for your desired consistency.

Color. A healthy starter looks the color of a regular flour and water mixture. However, if your starter turns pink, green, or blue, chances are you’ve accidentally introduced bacteria into the mix. Please don’t cook with a rainbow colored starter! (Remember, grey liquid on top is fine.)

Mold vs. Yeast.  When your starter is stagnant, you may see some small whitish, filmy dots on top. That’s nothing more than wild yeast. However if you see white, green, blue, or otherwise colorful fuzzy stuff growing upon your starter, it’s time to toss it.

A well-maintained starter can last for years on end. However, it’s always best to be cautious when in doubt. If for any reason your starter seems suspicious, throw it out and start a new one. The worst that could happen is the loss of a little flour and water.


Have you ever had a sourdough starter go bad? What did it look or smell like? We would love to hear your experience in the comments.


Abigail is an aspiring homesteader, homeschooler, and music-maker. She lives with her husband and three children on her acre-and a half homestead in scenic Pennsylvania. You can visit her blog about living the homegrown life (and seeking contentment while doing it) at They’re Not Our Goats.

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