One important part of home brewing kombucha that many new kombucha brewers get confused about is how to properly cover their jar of fermenting kombucha to keep bugs and unwanted debris out, while still allowing their kombucha to have enough oxygen to ferment properly. So how do you cover a brewing jar of kombucha?
Kombucha in its first fermentation should be covered with some type of breathable fabric such as a rag, cloth, old T-shirt, coffee filter, or paper towel, and secured with a rubber band or canning jar ring. First fermentation kombucha should never be covered or sealed airtight since some of the bacteria necessary for fermentation need oxygen to stay active and alive.
In this article I’ll share with you why kombucha needs to be covered, what types of things to avoid when covering kombucha, and what materials make the best kombucha covers. Let’s get into it!
Why You Should Cover Fermenting Kombucha
The reason that it’s recommended you always keep your brewing kombucha covered is to keep fruit flies, ants, food debris, or anything else you don’t want in your kombucha, out of your kombucha.
If a bug or piece of debris got into your brewing booch, it would not only make it really gross and possibly unsafe to drink, but it also could damage the living bacteria and yeast culture that ferments kombucha known as the SCOBY (Symbiotic Culture of Bacteria and Yeast).
Normally the SCOBY eats sugar and the nutrients from tea and ferments them into alcohol, acids, and carbon dioxide to create kombucha. But if other things like fruit flies or a small piece of plastic are in the kombucha, the SCOBY will try to eat these things.
And since it’s not healthy to eat bugs and plastic, if foreign items fall into a jar of brewing kombucha the SCOBY could become hurt, moldy, or even die.
Why to Never Use an Airtight Lid to Cover Kombucha
Most of the jars people buy to brew kombucha in come with a screw on or press on lid, and so new kombucha brewers rightfully wonder: Why can’t we just cover the brewing kombucha with the airtight lid the jar comes with?
The reason that you need to use a breathable material to cover your kombucha is because some of the living bacteria that ferment the kombucha need oxygen to survive and thrive.
If a brewing jar of kombucha were sealed airtight, there would be no airflow and the bacteria wouldn’t have any new oxygen, leading them to die off and your kombucha to not get made properly, or maybe even not ferment at all.
On top of this, if you use an airtight lid to cover your 1st fermentation of kombucha the carbon dioxide produced during fermentation won’t be able to escape the jar, and could build up enough pressure inside of the container to make it explode. Which obviously would not only ruin that brew of kombucha and possibly the SCOBY, but also make a very annoying mess to clean up.
If you need to transport your brewing kombucha from 1 place to another, you can put a lid on the jar for a short amount of time without any problems, just don’t leave it on for more than a day or two.
How to Properly Cover a Kombucha Brewing Container
So now that you know what not to do, but how should you properly cover a brewing jar of kombucha?
As long as a 1st fermentation of kombucha is securely covered with a breathable, non porous fabric, it shouldn't get any fruit flies, ants or other unwanted debris in it and have enough airflow to keep the living bacteria culture alive and functioning well.
Many people think of using cheesecloth to cover their kombucha since it’s a breathable fabric that they have at home. However, because cheese cloth is porous, fruit flies and other bugs can sneak through it and into your kombucha, which means it's not a good cover to use for your booch.
Some good materials to use to cover a jar of brewing kombucha are towels, rags, cut up cotton t-shirts, paper towels, and coffee filters. You can secure these covers to the jar with either a rubber band or a canning jar ring.
When I first started home brewing, I used coffee filters and a rubber band to cover my container until I cut up an old 100% cotton t-shirt into circles and used that.
Eventually when I bought this set of 2 one gallon glass jars they came with nice looking cloth rags so I just use those now.
Whatever material you use, just make sure that none of it is rubbing off and falling into the kombucha. Some people that use paper towels to cover their booch have had problems with small pieces of them falling into the kombucha, and when I was using the old t shirts to cover mine there was a small piece that fell onto my SCOBY at one point and I had to make sure I cleaned it off.
Final Thoughts
All kombucha brewing vessels need to be covered to keep fruit flies, ants, food, debris and anything else out. But, it’s important that the material used to cover the fermenting kombucha is not air tight since the living bacteria culture in the booch needs oxygen to survive and enact fermentation.
I hope this article was helpful for you and you could figure out how you’re going to cover your kombucha! If you’d like to learn more kombucha brewing tips, be sure to check out the rest of my website. Have a great day!