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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