Sourdough starter troubleshooting, part 2: Can this starter be saved?

In our first sourdough starter troubleshooting post we tackled sourdough starter viability, and what will and won’t cause your starter’s demise. We also found out what a spoiled starter looks like, and how to know when it’s time to throw it out and start over.

Today we’ll take on the thorny question of whether it’s worthwhile to try to revive an old but struggling starter — or if it’s best to start over.

Sourdough starter: a miracle in the making

Creating your own starter from scratch is exciting and even a little magical; for details, see our step-by-step guide to creating a sourdough starter.

Simply mixing flour and water allows friendly bacteria and wild yeast to join forces and establish a balanced ecosystem that is able to impart great flavor and rise to your sourdough baking.

Sourdough Starter Troubleshooting, part 2 via @kingarthurflour

During the 6 to 10 days that it takes to get your starter up and running, it’s a little more vulnerable to bacterial intruders and mold because it hasn’t yet developed the defenses of a mature starter. But once fully developed, a well-maintained starter will readily fend off unwanted invaders and is very unlikely to spoil.

Reviving a neglected starter vs starting a new one

What if you inherited an old starter from your grandma and it’s looking a little like it might be at death’s door?

Sourdough Starter Troubleshooting, part 2 via @kingarthurflour

Sourdough authorities argue that there’s nothing sacred about an old starter; a freshly developed “mature” starter will impart just as much flavor and rise to your bread.

Starting over with a new starter will get you back to baking great sourdough bread in a little over a week. So why take on the unpredictable task of trying to resurrect a sickly starter?

Common sourdough wisdom says that it will take just as long to revive a severely neglected starter as it will to create a new one. But is this always true? Click To Tweet

And is it even possible to thoroughly revive a starter that’s sorely neglected?

Let’s find out.

Sourdough Starter Troubleshooting, part 2 via @kingarthurflour

Sourdough Starter Troubleshooting, part 2 via @kingarthurflour

Starter showing any mold (or exhibiting an orange or pink streak) should be thrown away. But dark-colored “hooch” (the liquid sitting atop a neglected starter) isn’t a sign of danger.

I start with two very neglected starters. Both starters (one all-purpose, one whole wheat) had been well-maintained until they were left at room temperature for a full month without being fed.

Why test both a white and a whole wheat starter? Starters can be maintained with all different types of flour, so I wanted to see if a whole wheat starter responded in the same way as a starter fed with all-purpose flour.

Sourdough Starter Troubleshooting, part 2 via @kingarthurflour

Starter made with all-purpose flour

Sourdough Starter Troubleshooting, part 2 via @kingarthurflour

Starter made with whole wheat flour

I pour the dark hooch off the neglected starters, and feed them following the feeding schedule called for in our sourdough starter recipe.

The revived starters smell a little “off” at first, but not awful; think vinegary sour, with a slightly unpleasant edge. Within four days they’re rising well and have a nice, mildly tangy aroma. My theory is that both the acidity and the maturity of the neglected starters helps them fight off unwanted bacteria at the beginning of the process, which might allow for a faster return to a healthy and balanced starter.

Sourdough Starter Troubleshooting, part 2 via @kingarthurflour

Newly created starter

By way of comparison, I also begin a starter from scratch. My brand-new starter is able to keep up in terms of rise. However, after four days it still smells a little funky and doesn’t seem quite ready for baking bread.

Putting the starters to the test: Test bake #1

On Day 4 (after only four feedings) I bake Naturally Leavened Sourdough Bread using my revived starters (which I mix together for the test), and my regularly well-maintained starters.

Sourdough Starter Troubleshooting, part 2 via @kingarthurflourSourdough Starter Troubleshooting, part 2 via @kingarthurflourThe results are a little shocking: two beautiful and delicious loaves. Both loaves taste mildly sour, although taste testers agree that the revived-starter loaf is slightly tangier.

Test bake #2

On Day 5, after a total of six feedings, I try another test bake—this time including the brand-new starter; the revived starters, and my well-maintained regular starter.Sourdough Starter Troubleshooting, part 2 via @kingarthurflourAgain, the results are surprising: three nice loaves, each with a similar rise and crumb structure. The only real difference is in the flavor of the breads. Each has mildly sour flavor, but the brand-new starter yields a slightly blander loaf.

Sourdough starter troubleshooting: the takeaway

It’s definitely worth trying to revive a neglected starter (so long as it shows no signs of contamination). Pour off any discolored hooch, and start feeding it twice a day at room temperature. If it rises well and has a good aroma after three to four days, you’re back in business!

We’d love to hear your own sourdough starter stories and questions below. Did you revive your starter from the brink of death? How long did it take? Is it thriving now?

Barbara Alpern

Long time professional artisan bread baker, caramel maker and member of our Baker Specialist team, Barb grew up in Ann Arbor, Michigan and has four grown sons. She has baked in Michigan, Maine, Vermont, and Texas (if you count baking cookies for her son's wedding!).


  1. Carol

    After 10 days of beginning my sourdough start, it seemed really lackluster so I searched the internet for troubleshooting tips and read somewhere that if I fed it more flour than water, it would perk up. So, I fed it with about 10 grams more flour than water (70 g water to 80g flour) for a few days and it worked….I was able to bake 2 successful sourdough loaves but now my starter smells kind of like acetone. Is it safe to use?

    1. The Baker's Hotline

      Carol, a strong or funky smell is quite common when you change your starter’s feeding significantly. It usually just means that the yeasts and bacteria are settling into a new balance based on the available resources. While you probably don’t want to bake just yet (nail polish remover-flavored bread isn’t exactly popular), it should settle down into the familiar lemony-yeasty smell after a few days of feeding and discarding. Happy baking! Kat@KAF

    2. Barbara Alpern, post author

      Hi Carol, usually when a starter develops this type of acetone aroma it’s a sign that it has been allowed to go hungry a little too often. You didn’t mention what your maintenance routine was after baking your loaves of bread, but I suspect a few days of twice a day feeding at room temperature will solve the problem. If you happen to live in a very warm climate, your starter may be fermenting unusually quickly, so using cooler water may be helpful to slow things down. You could also try changing the ratio of starter to flour and water in order to slow things down. For example, you could try a ratio of 1:2:2 (starter: flour: water). For your particular starter this might look like saving 40g of starter and feeding it 80g of flour and 80g (or 70g, if you prefer) of water. However, I’d only resort to this if you find that the normal maintenance routine of feeding twice daily with the 1:1:1 ratio still results in an acetone aroma. Once the normal aroma of your starter returns you should be ready to bake again, or you can refrigerate your starter for up to a week. We recommend feeding your starter and allowing it to sit out at room temperature for 2-4 hours (or until it begins bubbling) before placing it in the refrigerator.

  2. Lynn

    Hi, I started my starter about six months ago, and love it. I bake with it every week and even use the discard. (no waste for me!) Love all your recipes and have great success. I went away on vacation for a week and accidently left out my jar of starter on the top of the fridge, not covered. There is a layer of yellow, thick, scum? (it looks hard) on the top. Is this still okay to use? Can I just throw out the thick, hard layer and use the starter underneath as usual, or do I have to throw out the entire starter?

    1. Barbara Alpern, post author

      Hi Lynn, there’s a very good chance that your starter will bounce back with a little extra TLC, so I would discard the thick layer on top and start feeding your starter twice a day at room temperature for a few days. Once your starter is bubbling nicely and rising predictably, then you should be back in business.

  3. Sandy Murray

    Great post! I started my San Francisco sourdough starter approximately 50 years ago in California as a new bride and I still use it quite successfully in Massachusetts now. However once I started baking in New England, the wild but much milder-tasting yeast took over (with either this starter or a fresh starter). Interestingly on a vacation trip I consulted with the oldest baker I could find in San Francisco about yeast quality. He also felt that even the San Francisco yeast had changed toward milder. We both lamented the lack of really sour flavor no matter how we’ve experimented. Different yeasts abound in different regions and they exhibit different aggressiveness. Still so much fun!

  4. Jo Partington

    Great to find this site. I am trying to revive my ‘Oxford’ and ‘San Fransisco’ starters that have been in Kilner jars (no rubber seal), in the fridge for 3 months as my husband has been in hospital. I was thinking after 2 days of no activity that they were gonners! They had a greyish/lilac coloured hooch which i poured off and I also scraped the first half inch of dough off before feeding. No signs other than the odd bubble, but I now have the confidence to keep trying. My husband is so looking forward to his sourdough toast when he’s home : )

    1. Barbara Alpern, post author

      Hi Jo, I hope your starters revive well, and you’re able to make that sourdough toast for your husband when he comes come! Don’t forget to take care of yourself along the way, and let us know how it goes.

  5. Dale Pearson

    My starter only rises about 10%. I started it with rye flour, and I feed it with KA AP as instructed. I only got a small amount of rise. After 2 weeks I decided to try one feeding with rye flour, and it grew to more than double! I continued to feed with AP, but never got the same rise. It’s been more than a week, and it never rises more than 10% per feeding. BTW, the aroma is amazing, and sometimes there is a slight amount of amber moisture on top. Can anybody tell me what’s going on here?

    1. Barbara Alpern, post author

      Hi Dale, you didn’t mention what type of container you have your starter stored in, but it’s easier to see the starter doubling in size if it’s stored in a container that is taller than it is wide. If your starter is stored in a wide bowl, than the rise can be a little more difficult to detect. It sounds like this probably isn’t the issue though, since you were able to see the starter double when you switched to pumpernickel flour. It’s possible that the wild yeast hasn’t fully kicked in with your starter, so it may be helpful to try a slightly different feeding regimen that will increase the acidity of your starter. I would suggest feeding with whole wheat flour once a day for a few days, using the ratio of 2 parts starter to 1 part flour and 1 part water. For example: save 4 ounces of starter and feed it 2 ounces of whole wheat flour and 2 ounces of water. Once you see your starter rising and falling predictably (which may take a few days) then switch back to feeding twice a day with the unbleached all-purpose flour, returning to the 4 ounces of starter:4 ounces water:4 ounces flour feeding routine. It may take a few days for your starter to adjust back to this routine, but eventually you should see the starter rising and falling predictably again. Once this happens, you should be good to go! Let us know how this works for you.

  6. Colleen Peloquin

    Hi! I am trying to make a starter. Should I change the jar at feeding? There seems to be some on the sides of the jar that is now turned to “cement”!

    1. The Baker's Hotline

      Coleen, we suggest using a rubber spatula to scrape down any bits sticking to the sides of your jar with each feeding and incorporate them back into your starter. If they’re cemented on, do feel free to transfer your starter into a different container for a bit to give your jar a thorough scrubbing. Happy baking! Kat@KAF

  7. Susan Leinheuser

    I have a locally grown starter (mountains of California) and my English muffins looked fine when I baked them, but the next day the crumb on the edges was grey. What caused this and are they still OK to eat?

    1. Barbara Alpern, post author

      Hi Susan, my best guess is that the grey color might be due to oxidation of the dough, especially if you opted for the overnight refrigeration. This is totally harmless, but you could try placing greased plastic wrap directly on the surface of the dough the next time you put it in the refrigerator, and see if this helps prevent the grey crumb.

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