Sourdough starter troubleshooting: What does it take to kill your starter?

“Did I kill my starter?” This is a surprisingly common sourdough question on our Baker’s Hotline. Novice and experienced bakers alike worry about the viability of their starters and call us for sourdough starter troubleshooting advice.

For many sourdough bakers, the underlying biochemistry at work in their starter remains a bit of a mystery. Thankfully, it’s quite possible to bake great sourdough bread while still being a little fuzzy when it comes to what’s actually happening in that little jar of starter.

The 6 to 10 days it takes to create a healthy and mature sourdough starter from scratch requires slightly more attention to “death threats,” because a fledgling starter hasn’t yet developed the defenses that characterize a mature starter. But once your starter is fully developed, it’s really pretty darn hard to kill.

And if you’ve purchased a sourdough starter from us, rest assured that it’s a mature specimen that will stand up well against unwanted bacteria or mold.

Sourdough Starter Troubleshooting via @kingarthurflour

Things that WON’T kill your sourdough starter

METAL: Stirring your starter with a metal spoon or placing it in a metal bowl won’t kill your starter. While we don’t recommend making or keeping your starter in contact with reactive metals like copper or aluminum, stainless steel is harmless. Sourdough Starter Troubleshooting via @kingarthurflourMILD NEGLECT: Missing a feeding or not timing the feedings exactly 12 hours apart won’t even come close to killing your starter. Please don’t ever set your alarm to get up in the middle of the night to feed your starter!

INCORRECT FEEDINGS: Feeding your starter the wrong amount of flour or water won’t kill it. While your starter may seem too dry or too wet, and may not rise the way you expect, no permanent damage has been done. You can correct its consistency by adding a little more flour or water, and then being more careful the next time you feed it.

BRIEFLY FREEZING YOUR STARTER: While there’s some dispute among sourdough enthusiasts about the benefits and/or dangers of freezing sourdough starter, a brief period in the freezer isn’t likely to kill a fully developed starter.

I recently froze a portion of my well-maintained starter a few hours after it was fed. Three days later I thawed it out at room temperature and let it continue to ferment. It was definitely sluggish at first, but after a second feeding it rose well and had a good aroma.

That being said, too much time in the freezer will definitely damage some of the wild yeast in your starter, and is also likely to kill off some of the friendly bacteria that contribute flavor. If you need to put your starter on hold for an extended time, we recommend drying your starter.

What does it take to kill a sourdough starter? When is it time to give up and start over? Click To Tweet

Things that WILL kill your sourdough starter

HEAT: If you allow your sourdough starter to ferment in the oven with the light on to keep it warm, and then forget it’s in there and turn on the oven, it’s unlikely your starter will make it out alive. Yeast dies at 140°F, and it’s likely that your sourdough starter will suffer at temperatures even lower than that. It’s best to maintain your starter at comfortable room temperature (around 70°F), though a little higher or lower won’t hurt anything.

SEVERE NEGLECT: If you neglect your starter long enough, it will develop mold or signs of being overtaken by bad bacteria. Mold can appear in various colors and is typically fuzzy in appearance. Bad bacteria is generally indicated by an orange or pink tinge or streak. Once your starter has lost its natural ability to ward off intruders, it’s time to start over.

Sourdough Starter Troubleshooting via @kingarthurflour

How to tell if your starter has gone bad

“Hooch” is the liquid that collects on the top of your starter when it hasn’t been fed in awhile. This liquid is the alcohol given off as wild yeast ferments. The presence of hooch isn’t a sign that your starter is in danger. However, it does indicate that your starter is hungry and needs to be fed.

When your starter is neglected for an extended period, the hooch tends to turn from clear to dark-colored. We get lots of calls from sourdough bakers worried about the safety or danger of various hooch hues. Is gray bad? What about brown or black? Surprisingly, none of these colors indicate that your starter has spoiled.

Sourdough-Starter-Troubleshooting via @kingarthurflour

See the orange streak? This starter shouldn’t be saved.

However, if you see a pink or orange tint or streak, this is a sure sign that your sourdough starter has gone bad and should be discarded. The stiff starter above was left out at room temperature for two weeks. It’s definitely time to throw it out and start over.

Sourdough starter troubleshooting: points to remember

1. Well-maintained mature sourdough starters are extremely hardy and resistant to invaders. It’s pretty darn hard to kill them.
2. Throw out your starter and start over if it shows visible signs of mold, or an orange or pink tint/streak.

I hope you’ll share your own sourdough starter questions and discoveries below. There’s always more to learn when it comes to sourdough!

And please check out part 2 of this sourdough starter troubleshooting post!

Barbara Alpern
About

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!).

comments

  1. Dani

    My Dad has had 75+ year old sourdough starter for 25 yrs. He’s always loved the bread making process. He passed away a week and a half ago. One of his main wishes was to keep that starter and bread alive and going. He used sugar, potato flakes and hot water to feed. The smell isn’t quite as strong in the starter right now and I absolutely cannot get the dough to kneed and not be flakey. I don’t want to give up but feel at a loss! HELP PLEASE 🙂

    Reply
    1. Barbara Alpern, post author

      Hi Dani, we’re so sorry for your loss, but it’s wonderful that your dad left you this baking legacy to remember him by! I don’t have any experience with this type of starter, but there’s lots of information and recipes online. Here’s an article you might find helpful. As far as the consistency of your bread dough goes, it sounds like you may be adding too much flour, which is easy to do if you measure your flour by cups and tend to scoop the flour into the cup. For best results we recommend either weighing your ingredients, or using this method to measure flour by volume. I hope this helps. Let us know how it goes!
      Barb

  2. Txgrl

    Hi
    I’m new to sourdough baking, and am trying to make my own sourdough starter, I am currently on day 3 but I’ve already noticed that my starter has risen and fallen. It also had a smell of vomit. I live in Tx and used whole wheat flour to make my starter. There are no other obvious bad signs of that posted on this page but I did notice a slightly clear liquid on the bottom of the jar. Should I discard my starter or still continue to feed it?

    Reply
    1. Barbara Alpern, post author

      Hi there! Yes, by all means keep feeding your starter! It’s not unusual to experience off odors at some points during the starter creation process so there’s no need to be alarmed. The clear liquid doesn’t sound worrisome either. It’s also not uncommon to see the starter rise and fall during the first few days of the process, although this may be due to bacteria that give off carbon dioxide, rather than wild yeast activity.
      Barb

  3. Austin Sc

    Hi, I’m making my first starter, the first 2 days it look okay and I was feeding it twice daily. However on day 3 my starter had a pinkish color above the hooch, no bad smell, just a pink tone on the top. Is it bad? Should I throw it out? I been feeding different flours because I kept running out, is that bad?

    Reply
    1. Barbara Alpern, post author

      Hi Austin, if you’re seeing a pink tone so early in the process my inclination would be to start over. Be sure to clean your container and tools with very hot water, and dry them thoroughly before beginning again. I’m not sure what flours you’re feeding your starter with, but I would try to stick to either whole wheat or whole rye for the first feeding, and then switch to unbleached all-purpose flour. If you want to continue feeding with whole wheat flour once a day until the starter begins rising and falling predictably (this can take several days), and then switch to feeding unbleached all-purpose flour twice a day, that can also work well.
      Barb

  4. John Martin

    my first attempt at making a sour dough starterhasn’t been very successful so far. I followed the instructions in the recipe using 4 ounce of plain flour and 4 ounce of water, I fed the mix once a day as per the recipe with the same amounts of flour/water. All looked good until day four, there was quite a lot of hooch on top and the smell was a bit unpleasant like very sickly vomit not at all like yeast. there wasn’t any color to it but the mix was very thin. I gave the whole lot a good stir and discarded all but 4 ounces to which I added 2 ounces of flour and 2ounces of water, so far it looks ok with bubbles forming after a couple of hours with only a slight smell but not unpleasant as before. Have I done the right method to recover the mix, and should it smell the same as baker’s yeast once mature. My late Father owned a small bakery in the East End of London, England but he never made sourdough. I did not follow in his profession but but gained some knowledge from helping at busy times. As sourdough bread has become more available and popular in supermarkets and small independant bakeries I decided to give it a try

    Reply
    1. Barbara Alpern, post author

      Hi John, are you feeding with whole wheat flour? This can help increase the activity level of the wild yeast if your starter seems to have hit a lull. Try the 4 ounces starter + 2 ounces whole wheat flour + 2 ounces water formula once a day for a few days until the starter begins to rise and fall predictably, and then switch back to the 4 ounces starter + 4 ounces unbleached all-purpose flour + 4 ounces water twice a day until the starter begins again to rise and fall predictably. The aroma of a mature starter won’t exactly be like baker’s yeast; I would look for a mildly tangy aroma when the starter has been fed and allowed to ripen for several hours. Don’t worry if you don’t detect much of a sour aroma as long as the starter doesn’t have an unpleasant smell. A consistent pattern of rising and falling is the best predictor that your starter is ready to be used in your baking.
      Barb

  5. Joshua

    Hey there! Started my sourdough from scratch, and I’m on day 10. Pretty much ever since starting 2x daily feedings the starter has slowed down significantly.

    Day 3-4 everything was fine and the aroma seemed perfect from all my research.

    Day 5-8 my dough seemed thin (probably due to not having a kitchen scale), but it kept chugging on producing small bubbles, but never rising.

    Day 9 I got a kitchen scale, and days 9-10 after using the correct 1-1-1 ratios my dough seemed pretty thick (stuck and hung from the spatula when you stuck it in). Much fewer little bubbles than when it was thin and STILL isn’t rising, but the smell seems close to correct… maybe a bit shy of what I would expect in terms of strength of aroma.

    I’d like to think that the thing is still alive and working, but I thought it would happen by now. Am I doing it right? Should I keep going or should I change it up somehow?

    Gotta say (being new to this baking thing) this sourdough thing is more suspenseful than I expected lol. Thanks for the help!!

    Reply
    1. Barbara Alpern, post author

      Hi Joshua, what type of container are you storing your starter in? It’s more difficult to see a significant rise if you have it in a wide bowl, rather than a taller quart-sized jar. You do want to see the starter rise and fall predictably in order to consider it mature, so it may be helpful to tweak your feeding routine and see if this helps kick the wild yeast into gear. Since you now have a scale, try switching to feeding with whole wheat flour once a day with the following ratio of ingredients: 4 ounces starter:2 ounces flour:2 ounces water. This will increase the acidity of the starter and should help get the starter rising. Once you see the starter rising and falling predictably within approximately 12 hours, then you can switch back to the normal feeding schedule with AP flour twice daily in the 1:1:1 ratio by weight. Once the starter is again rising and falling predictably, you should be good to start baking!
      Barb

  6. Bad Baker

    I was given a started by a friend over a year ago and kept it sealed in the fridge (not fed it once!). Shall I try or just throw it? Doesn’t smell too funky but has gone stiff? Grey liquid on top…? Would it suprise you to hear that I’ve never baked bread before!

    Reply
    1. Barbara Alpern, post author

      Hi there, I always think it’s worth trying to revive a neglected starter, as long as your not seeing any mold or bad bacterial growth. The first feeding you’ll probably have to add extra liquid to get it to be the correct consistency, but I’m guessing after 3 or 4 days of twice a day feedings at room temperature you may well see some good activity. The tricky part is determining if you’re actually reviving your starter or creating a new one from scratch, since the feeding process is similar, and you’re likely to see activity after a few days in both cases. Look to see that your starter is rising and falling consistently within a 12 hour period and has a slightly tangy aroma to determine if your starter is mature and ready to use in your baking. A revived starter will usually only take 3 or 4 days to return to normal activity, while a starter that is created from scratch can take around 10 days to reach maturity.
      Barb

  7. Moriah

    My starter is several months old, KA bread flour and whole wheat. It has a really awesome bubble to it and I do regular feedings. Today I can’t tell if tge top is orange in a large swatch or its just excess wheat. If its so bubbly could it still be bad? It smells ok…

    Reply
    1. Barbara Alpern, post author

      Hi Moriah, if you’ve been feeding your starter regularly, and don’t allow it to sit out at room temperature for an extended time (several days) without feeding, I suspect your starter is probably fine. I would suggest removing a large section of the top layer and then feeding the remaining starter at room temperature twice daily for a few days. If it seems to be rising well and has a good aroma, I’d say you’re good to start baking again!
      Barb

  8. Nikarta

    Hi – my starter is now about 3 weeks old and has produced a couple nice breads. 3 days ago I have noticed a rather bitter taste and was wondering if that is only temporary or normal. Is there anything that I can do in terms of type of flour for feeding? It was started on rye and KA whole wheat and the feedings are now with white KA flour and KA whole wheat. Somebody told me that the taste is the result of a particular bacteria….

    Reply
    1. Barbara Alpern, post author

      Hi Nikarta, assuming you’re still feeding your starter fairly consistently, I doubt the bitter flavor has anything to do with unwanted bacteria. Is it possible your whole wheat flour is out of date? Whole wheat flour can go rancid over time and this could contribute to an off flavor in your starter or bread. Once you’ve checked that your flour is fresh, I would resume twice a day feedings at room temperature and see if this improves the aroma and flavor of your starter and bread.
      Barb

  9. Soomi Chun-Derradji

    I am a new bread baker and trying my hand at starting a sourdough starter from scratch. It’s day six and I’m not sure if it’s going the way I read it should go. I sealed the top of my jar are everyday there was activity and rising until day 4 where I loosely closed the lid,as per instructions and everything died down with only a few bubbles and no yeasty smell. I’m thinking I should throw it out?

    Reply
    1. Barbara Alpern, post author

      Hi Soomi, the decline in rise and activity level that you noticed around day 4 is not uncommon, and is most likely entirely unrelated to how tightly you closed the lid. The earlier activity you noticed may have been primarily due to a type of bacteria that gives off carbon dioxide, and the lull you’re experiencing can be due to a related delay in wild yeast activity. In order to encourage the wild yeast to kick in it’s helpful to adjust your feeding routine a bit to increase the acidity of your starter. I would recommend returning to feeding your starter with whole wheat flour, feed only once daily, and increase the proportion of starter to flour and water to a ratio of 2:1:1. For example, try feeding your starter by keeping 4 ounces (1/2 cup) of starter and feeding it 2 ounces (1/2 cup) whole wheat flour and 2 ounces (1/4 cup) water for a few days. Once you see the starter rising and falling predictably you can return to feeding twice daily with the unbleached all-purpose flour at the 1:1:1 ratio of 4 ounces each of starter, flour and water. Once your starter is rising and falling predictably with the white flour feedings, then you should be good to start baking!
      Barb

  10. Douglas Black

    I made a starter well over a year ago that I use on average every 2 weeks, keeping it in the refrigerator in between. It has always been healthy and started right up, every time. I recently got busy and was unable to touch it for 6 weeks… It was not discolored but smelt more sour than usual and is not rising yet after 2 days of feeding/discarding/feeding. It just seems like flour paste…
    Patience? Or panic?

    Reply
    1. Barbara Alpern, post author

      Hi Douglas, I think I would exercise a little more patience and feed it for another day or two. If your home is particularly cool this time of year you may want to find a slightly warmer spot for your starter to dwell (70-80 degrees) and see if this helps increase your starter’s activity. If your starter doesn’t respond to this, then it may be time to start over.
      Barb

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