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!

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!




also, is there something i can do to increase the acidity of my batch b/c i didn’t add enough starter tea, to save a given batch?
by the way, the info on herbal teas weakening the tea is great to know.
gary
Hi Gary, yes, you can add a splash of distilled white vinegar or some strong finished kombucha to boost acidity if your starter tea was too low. Just add a little at a time and taste as you go so you don’t overdo it.
my scobee didn’t make a new baby! there was a thin film on the top but it didn’t look like any of the photos. i tossed it. ugh. i was able to skim it off the top w/ no issues. thoughts?
i have a feeling you will tell me to start off and toss it.
thanks for the help.
gary
That happens sometimes, especially if the batch is young or conditions weren’t ideal. A thin film that’s easy to skim off (rather than a thick rubbery layer) usually just means the new scoby hasn’t fully developed yet. If your kombucha tastes and smells right, it’s probably fine, no need to toss it next time unless you see fuzzy spots or fuzzy texture.
Hey I just started my first kombucha. Itโs been fermenting for 4days. Iโm unsure about the layer on topโฆ can I email a picture? Itโs doesnโt look like any of the above.
Hi Courtney! I totally understand wanting a second opinion. Feel free to email me, [email protected].
I started a kombucha on Wednesday mid day and itโs Sunday mid day the little scoby I brought from health shop has sunken to the bottom. I donโt know because this is my first time but I think itโs mould growing on top now. I use 4 cups of green tea, 8 cups of water and 3/4 of sugar ( only had castor sugar) it now has white looking spots on top.
Hi Sally! It’s hard to say for certain without seeing it, but a sunken scoby by itself isn’t a mold sign, that can just mean a new baby scoby hasn’t formed yet. White fuzzy spots that sit above the liquid line and look dry or cottony are the real mold red flag. If it smells sour and yeasty rather than off or rotten, it’s likely fine, just keep monitoring.