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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105 Comments

  1. Mariana says:

    I’ve started making kombucha a few days ago and today I noticed a bit of mold and it got me scared. However I only intend to make biomaterials out of this kombucha, so whether it’s safe for consumption or not is not a concern for me. Is there still hope that the kombucha will produce a scoby and eventually kombucha leather aswell?

    1. Sarah Bond says:

      Hi Mariana! It will likely still produce a SCOBY, but if the bacteria become too out of balance it may not.

  2. Debra Woloshyn says:

    How can I get a new scobi??? Can I make my own?

  3. Debra Woloshyn says:

    I just had a batch go moldy…yuk! I did have my scobi in the fridge so thinking that was the cause. I thought since I was not able to make a new batch for a couple of weeks (went away on vacation) I should put it in the fridge. I have refrigerated before without problems…maybe I just got lucky? Anyways I am bummed and now have no starter…can I make one???

    1. Sarah Bond says:

      The cold temp increases the chances of mold, sadly! Just grab a bottle of unflavored from the store and you’ll have a fresh batch in no time!

  4. Sandee Warzabluk says:

    I would like to send you a picture of what I wonder is mold.

  5. Colleen says:

    Hi Sarah
    A few months new to brewing and wondered why my Kombucha wasn’t fizzy. This led me to your website! Question on sugar. Is there a certain type of sugar that is best? I am using Cane sugar, Is this ok?
    Many thanks

    1. Sarah Bond says:

      Hi Colleen! So sorry for the delay. Cane sugar should work well! I have an article for the best sugars for kombucha here ๐Ÿ™‚

  6. Keira Rogalla says:

    If I have been brewing for three months but will be out of town for two and a half weeks and dont have anyone that can start and bottle for the second/last fermentation what should I do? I don’t want my scoby to go bad but I can’t take the stuff for brewing with me.

    1. Sarah Bond says:

      Add some sweet tea to it and it should be fine! That’s enough “food” to hold it over for that length of time.

  7. Francine says:

    I have three Scobies I stopped brewing and stopped making the kombucha and left them in the tea for over three months and a half are they still good? They look white on the top and hard and they look like they have grown a lot as well. Just wanna know if I have to get rid of them, I feel bad I went through a terrible trial and I had stopped working on my Kombucha, what should I do?

    1. Sarah Bond says:

      Hi there! As long as there isn’t any mold, you should be fine! Always use your best judgement when it comes to taste and smell ๐Ÿ™‚

  8. Rossy says:

    Hi!! First time kombucha brewer here. I want to ask you if this on my kombucha is mold or just a scoby forming. Please tell me that I didn’t lose this 14 days waiting patiently for nothing How can I send you the pictures?

    1. Sarah Bond says:

      Hi Rossy! Feel free to post a photo in our Facebook group where I and many other brewers can help you out!

  9. Emily says:

    I think my issue was not enough starter tea in the batch. But I donโ€™t have much left with my other (non moldy) scoby since I was going to put some of this batch with itโ€ฆ what do you recommend?

    1. Sarah Bond says:

      I would recommend grabbing a bottle of unflavored kombucha from the store to help supplement it until you have enough homemade!

  10. John says:

    I have mold floating on top of brew circular with blue center. Is the Scoby still good or do I need to get a new scoby
    Thank you
    John

    1. Sarah Bond says:

      You’ll need to start again with a fresh SCOBY and starter tea unfortunately. The mold has tiny spores that can infect future batches.