How can you tell if your kombucha has mold? And can you save a moldy SCOBY? Diving into your worst kombucha nightmare (and how to prevent it) here!

Picture of kombucha SCOBYs with and without mold

It’s every kombucha brewers worst fear…mold. But is it really as scary and world shattering as people seem to believe? No.

The thing is, kombucha mold is totally avoidable, and the chances or contracting mold are quite low if you’re brewing kombucha properly.

What is kombucha mold?

Kombucha mold is simply an overgrowth of bad bacteria or fungus. It isn’t much different than the mold that might grow on an old loaf of bread.

And while you shouldn’t drink any kombucha that has been in contact with mold (just as you wouldn’t eat that moldy bread), it’s not the end of the world!

What does kombucha mold look like

Though the chances are low, if mold is going to happen it will likely be in the first fermentation, when the kombucha acidity isn’t high enough to fend off the bad bugs. Once kombucha is bottled in the second fermentation, the acidity of the brew should prevent mold from growing.

While there are many different strains of mold that can grow – each with their own unique appearance – they usually have a few specific traits:

  • Fuzzy or dry appearance
  • Circular shape
  • Colors range, but may be white, green, black, or blue
  • On the surface of the kombucha (most mold needs air to survive)

Here are a few photos of kombucha mold for your reference. (Have a moldy SCOBY photo and want to include it in this gallery to help more people ID potentially moldy kombucha? Email me!)

(If your kombucha looks odd but it doesn’t look like mold, you could have kahm yeast.)

How to prevent mold in your kombucha

If you got mold, it’s because something went wrong in the process of brewing. Here are a few common reasons you may have got mold:

Not enough starter: If you didn’t use enough starter kombucha, or the starter wasn’t strong, the kombucha may not have been acidic enough to defend itself from mold strains. You can use pH test strips to ensure your starter kombucha is strong and acidic (should be between 2.5 and 3.5).

Temperature too low: If the temperature is too low where you’re brewing, or if you put your first fermentation / SCOBY in the fridge, the bacteria and yeast go dormant. This means they can’t acidify your kombucha, and mold may grow. Never store your SCOBY in the fridge, and ensure you store your kombucha somewhere warm enough to prevent mold.

Supplies not clean enough: Mold spores may have slipped in through your supplies, such as if you used a dirty sponge to clean the jar. Learn to clean your supplies to prevent contamination.

Used the wrong ingredients: Herbal teas and different sugars can weaken the SCOBY over time. Be sure you’re using the best teas and best sugars for kombucha.

Wrong place: Where your fermentation station is located matters! Airborne contaminants from garbage, compost, fruit bowls, or even other fermentation projects (likeย kefirย orย kimchi) can contaminate your kombucha. Ensure your kombucha is stored away from these.

What if I’m not sure?

The thing is, kombucha looks weird even under normal circumstance. So what if you’re not sure?

Just give it a few days! If it’s mold, it will grow to look like something in the photos above. If it doesn’t grow, it’s probably just normal, weird kombucha stuff.

Here are some examples of normal kombucha SCOBYs for your reference. Not sure if yours is moldy or not? Feel free to ask in our Facebook group!

You got mold, now what?

First off, my condolences. Now it’s time to make your peace and throw it all away. The SCOBY, the tea, everything. There may be microscopic mold spores that you can’t see in the kombucha, so you’ll need to toss out the whole batch.

Next step, sterilize everything very well using boiling water and distilled white vinegar. (Here’s how I sterilize my kombucha supplies).

Finally, learn from your mistakes and move on. Figure out where you may have gone wrong so you can prevent mold from ever happening again. Can’t figure out what went wrong? Read the kombucha master recipe again closely in case you missed something. And feel free to email me with your questions!

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99 Comments

  1. Karen says:

    When I bottled my last batch of Kombucha, I had to divide up my scabby….it was about 2″ thick. I made a new batch and it has been brewing for about a week now and a noticed a thin layer of Mold? new scabby? on top of my jar. It is kind of silver grey and a lot of bubbles around the edges. I took a photo but don’t know how to send it with this message. Thank you.

    1. Sarah Bond says:

      Sounds like that’s just a new SCOBY! ๐Ÿ˜€

  2. Linda says:

    Hey, I have a batch of kombucha I just did a few days ago. I have been checking it but today it had this weird grey/black/brown spot that from the side resembles a good ferment of sour dough start. But looks weird from The top. Smells good, but to nervous to test as I have test bad batches of ferments before and gotten sick. I was looking at the list of mold pictures and healthy one and non of them look like what is going on with mine. So I don’t know what to think.

    1. Sarah Bond says:

      Feel free to post a photo in our Facebook group to get some brewer opinions!

  3. Andrew says:

    Thanks for your prompt reply,
    I think I used to much tea like I said it tastes ok,
    Question what is the best number of days before moving to the fermentation stage?
    Thanks for your help,

    1. Sarah Bond says:

      That really depends on a lot of things, like how warm it is in your house and what flavor you like. Pellicle/SCOBY is ready at about 1/4 inch thick. Then you run the fermentations until the kombucha tastes good to you! Here’s our guide to making kombucha start to finish.

  4. Andrew says:

    Hi
    Good afternoon
    I am brand new to this, ok I’ve brewed beer and cider before, I’ve started my first scoby question 1 it tastes ok but still looks very dark is that ok? I may have used to much tea,
    question 2 how do I store the scoby after I complete the fermentation?

  5. Shelrae Stanley says:

    I bought a kit with an organic scoby. After 6 days thereโ€™s a thin white film on the top. Is that mold? I think I made a mistake by using 9.5 alkaline water for my fermentation. I also used organic raw sugar. Did I use the wrong sugar too?

  6. Sabrina says:

    I have some weird black thing growing on the side of my new scobby anyone experience this before.
    Looks like scobby poop.

    1. Sarah Bond says:

      It’s probably yeast if it’s wet, but feel free to pop a photo in our group for some feedback!

  7. Ali says:

    My friend gave me a scoby and didn’t tell me not to store it the fridge! I don’t have all my supplies for my first ferment yet so I thought the fridge would be the best place for it. Did I kill it? Or will it be ok once it warms back up?

    1. Sarah Bond says:

      It should be okay, but I would take it out of the fridge now until you have all your supplies ๐Ÿ˜€

  8. Aubrey says:

    Hi Sarah! I may’ve missed this in the article, but do I throw out the SCOBY from my moldy Kombucha? Or can I cut off the top layer? Sorry, I’m a kombucha newbie ๐Ÿ™‚

    1. Sarah Bond says:

      You’ll need to toss out the SCOBY unfortunately. Mold in kombucha can spread mold spores all around the jar, so it’s more likely to come back if you use the same SCOBY.

  9. Annika says:

    Hi
    I am a returning reader and love the blog.
    So I got a little scoby last week from my mom as a birthday gift. Today is the 7th day and it is weird looking, tho a little bubbly. So I applied for membership in the FB group to get some acknowledgment that it is doing just fine, because i cant enlarge the pictures with the good looking scoby. Hoping to be accepted. ๐Ÿ™‚

  10. Robbie says:

    I tried to make a batch of Kombucha but it went moldy, at the time I just took the moldy scoby out and some liquid from the batch and threw it away before topping the same batch up again. Now a few weeks later there is no sign of more mold growth, do you think it would be okay if no new mold seemed to grow?

    1. Sarah Bond says:

      If you don’t see any mold then I think it should be good to go!