Is it Mould on my SCOBY? How to recognise Mould on a Kombucha SCOBY!

Once you have seen Mould on Kombucha you will be a pro in recognising good Kombucha SCOBY's from mouldy ones. You are reading this because you probably have never seen mould on a Kombucha SCOBY before. Let me help you to find out if you have a perfectly healthy SCOBY that may look a little funky or if you unfortunately have mould growing on your kombucha SCOBY.

In general it is very rare that a Kombucha SCOBY becomes mouldy. I have made over 10,000 brews and only a handful of times have I had mould growing on my kombucha SCOBY. The first time my kombucha SCOBY had mould, I knew straight away that it was mould and the few points and pictures below should bring you some clarity.

  • Mould can only be on the surface of your SCOBY which comes in contact with the air. Therefore if you see some brown dark stringy stuff hanging below the new film on top of your kombucha brew(your baby SCOBY) then that is completely normal and is just yeast growth, which is totally harmless.

  • The best way to know if you have Mould on a SCOBY is that it looks like the mould that you would get in a jam jar. Its furry and often green or black. It can be partially white but is furry and has usually a green or black core.

  • If you are still not 100% sure then it helps to just wait a few more days to see how the SCOBY develops and to see if the suspected mould grows or spreads.

 Recognising the difference between Mould and Yeast on a kombucha SCOBY

What to do if you have Mould on your kombucha SCOBY?

  • Unfortunately you must discard the whole kombucha brew including your SCOBY and start fresh. 

  • Ensure you wash your kombucha jar very thoroughly and clean your tap. Cleaning the tap is very important as you could have a SCOBY formed inside and mould could have spread throughout your kombucha batch contaminating the SCOBY now inside your tap. Without removing or cleaning your tap and kombucha jar thoroughly, when you make a new batch of kombucha it is highly likely you will get mould again, this is a common issue when people neglect cleaning their tap properly. Watch this video on how to clean the inside of your tap.

What can you do to avoid getting mould on your kombucha SCOBY?

  • Keep your kombucha brew preferably above 20°C or in the fermenting range. This is very easy to do with a heat mat! I always highly recommend a heat mat as majority of kombucha SCOBY mould cases are due to allowing your kombucha batch to drop out of the fermenting range temperature. The lower the temperature the more dormant your kombucha becomes. 

  • Always use strong kombucha starter liquid or use more kombucha starter liquid if its not that strong. Instead of the recommended 10% I would use 20%.

  • Keep your kombucha jar always covered with a cloth to prevent foreign microbes and insects contaminating your kombucha brew.

  • Maintain a clean environment, avoid keeping your kombucha batch near the rubbish bin.

  • Keep house plants in a different room to your kombucha batch.

  • Avoid keeping your kombucha batch in the pantry as there is less air circulation and there could be foods in the pantry that can contaminate your kombucha batch without knowing. 

Can you recognise what is mould on a kombucha SCOBY? 

Mould on a kombucha SCOBY, how to recognise if it is mould or yeast


Yeast on a kombucha SCOBY not Mould


  • Joshua Heal

    Hi Belinda, if you want you can filter out the black stuff(yeast) when bottling your kombucha if you don’t want to drink it. Karl and myself leave in the yeast as we don’t mind it being there. Just keep in mind that the yeast is what makes your kombucha fizzy in the second fermentation so if you really don’t want it in your kombucha I would filter it out after it has finished it’s second ferment and is fizzy 😊I have attached a link to how to create fizzy kombucha.
    I hope this helps, Cheers Josh

  • Joshua Heal

    Hi Jason, yes if you are unsure then send them to us in an email to and we will confirm if it is mould, yeast or something else 😊

  • Joshua Heal

    Hi Jason, yes if you are unsure then send them to us in an email to and we will confirm if it is mould, yeast or something else 😊

  • Belinda

    Thank you for your photos and explanation. This was VERY helpful and gave me comfort that I did not have mould growing. This is my first time brewing and mine looked like the first photo. But, should I remove the black stuff or leave it?

  • Jason Chambers

    Can I send you a picture to see if this is mould or not?

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