Finding mold on your kombucha is always a sad day. You WILL KNOW if it is mold. Many times you will look at your young kombucha brew, wondering to yourself if what you are looking at is mold. If you have to ask yourself that, it is MOST likely not mold, but a pellicle, SCOBY, forming. If the word pellicle is new to you, be sure to check out our post, What is a SCOBY? for clarification. SCOBY or pellicle growth is rarely uniform and can resemble circular patterns that mold spores make. So give it a day or so, the dots will soon start to connect into the pellicle that you were expecting. Kombucha mold is the same mold that grows on our bread, so we have all seen it a million times before, and you will instantly recognize the fuzzy little ruiners of your day.
Moldy kombucha can be avoided with a little bit of care and prevention.
Step 1: Clean your work environment
Mold spores, just like bacteria and yeast, are omnipresent in our world and are one of the main forces we combat to maintain cleanliness in our lives. It is important NOT to give mold an upper hand and properly sanitize your vessels, tools, and counter space before brewing. You can do this by using soap and hot water, a vinegar and water solution, or by using Star San, a popular home brewing acid sanitizer that is safe for consumption. Since I do a lot of brewing, I use Star San and keep it readily available in a spray bottle nearby. Even if you don’t do a lot of brewing, it is nice to have around to clean your wooden utensils and cutting boards; anything bacteria can seep into. If you do use soap and water, try a natural product as many soaps leave residue on the surface that can interfere with the health of your SCOBY.
Step 2: Ensure a low pH
It is difficult for mold to grow on solutions that have a pH lower than 4. You can achieve this by adding 10 percent “starter tea” to your brew, or 12 oz for every 1 gallon. Starter tea is simply aged kombucha tea. If you bought one online, the SCOBY should come packaged with enough liquid to brew mold-free safely. If for some reason, you cannot locate starter tea and all out of options, you can substitute 2 TBSP of distilled white vinegar- never raw vinegar, and that should do the trick.
Step 3: Choose the right spot to store your brew
The ideal place for your kombucha during fermentation is in a cabinet, away from sunlight and moisture. The moisture aspect is important because mold is attracted to moisture and will be more prominent in areas such as under the sink or near the stove. If you don’t have any extra cabinet space (I feel you there!), the countertop is fine, just throw a tea towel around it. If you’re feeling fancy, they sell porcelain fermenters that sit on the counter and allow for a continuous brew, meaning you really wouldn’t have to worry about mold ever again if you make it through the first batch. Mold also cannot grow if you disturb the surface. If it’s going to grow, it’ll grow in the few days. In those three days, if you give the surface a swirl with a clean spoon of sorts, you should feel pretty confident that you have defeated the mold. You can go about your next seven days-ish forgetting about the batch until you want to taste it and see if it is done!
If you follow these guidelines, you will be one happy kombucha brewer. If you do happen to find mold, throw it out and start over. This is when a SCOBY hotel becomes a clutch addition to your fermenting toolbox. Check out my post on how to make one if you don’t know what a SCOBY hotel is!
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I bought a Scoby from your site, followed directions and at around the 7 day mark noticed a scum forming around the outer edge of my jar. It didn’t look like mold so I left it. At 11 days the scum looking stuff was about 1 1/2 in thick around the edges. I stored the mixture then strained it. I don’t know what it is suppose to taste like but it tasted like my sugar tea used to when I let it sit to long without drinking it. Also it didn’t get a ‘ baby ‘ Scoby. Wasn’t it suppose to ? Wondering what I did wrong.
What is the room temperature that you keep it at? If it is too cold, the fermentation process will be halted. By too cold, I mean below 75. Not sure what the scum would be, other than an odd-looking scoby forming but the scoby should be somewhat uniform and grow on top.
The section about Step 2: Ensure a low pH. You say you can substitute 2 TBSP of distilled white vinegar and that should do the trick. Can I use Bragg’s Apple cider vinegar “With the Mother” instead?
Hi Donald!
Apple cider vinegar can contain “vinegar eels” that are harmless to humans but over time can harm your SCOBY culture. If you’re pH is not below 4.5 from the beginning, you should use plain distilled white vinegar to lower it. For future brews, you’ll just use more starter tea from your previous batch.
Hey Ruthie~ I an new to Kombucha but have had some recently and love it! Was told how easy it is to make` so I have gallon glass jar for tea and a smaller jar for baby…I have my 16 oz glass beer bottle with snap lids…so I am getting ready…one question I have …after I order a scoby with the starter and put in my tea and let it sit for 7-10 days…if it works…I will end up with 2 scoby s right…(so I put both in the smaller glass jar.. with some of the tea .does it go in the refrig or back in a dark spot??? for tea at a later time??? thank you so much for any help Shelia/VA
Hi Shelia!
Every time the surface of the tea is disturbed, a new SCOBY will begin to form on the new liquid surface. You don’t necessarily have to separate the SCOBYs every time, but once your jar becomes crowded you can move the older SCOBYs to a “hotel” in a separate jar with a little tea in it. If you want to take a break from brewing, keep the jar at room temperature with enough liquid to cover the SCOBYs. Every now and then you will want to swish it around so the liquid makes contact with the top of the SCOBY–otherwise you could run into issues with mold.
Hello!
I’m new to Kombucha, bought the scoby through y’all (amazon) and I was going to have a taste today (day 9) and think I see mold. I’m so bummed! It’s on top of the newly formed scoby (your scoby is still at the bottom of the container). I have a decently established scoby formed at the top, with an occasional brownish slimy looking thing under the scoby, but the mold looks like a small fuzzy spot, mostly white but with a green center, raised, dry. Room temp is 76 degrees and pH is about 3.5. I read this post and, while I didn’t inspect it thoroughly in the last couple of days I believe this appeared well after day 3. Should I toss it? Give it some more time?? TIA.
Hillary, can you send me a photo to info@fermentaholics.com so I can take a peek?
I have Heinz pure vinegar. 5% acetic acid by volume. Can I use that to reduce the pH of my kombucha? I live in a rural area and i could not find distilled vinegar in my store.
Hi Susan,
The best way to lower your pH is to use more starter tea. If you don’t have more starter, then you can simply make a smaller batch so that your ratio is higher. The only reason to use vinegar is if the ph of your water source is particularly high or if you don’t have any starter tea to begin with.