Kombucha, a vinegar cousin, is fermented by organisms that build their own house at the surface of the liquid. This SCOBY, or Symbiotic Culture of Yeast and Bacteria, is another cellulose pellicle common to vinegar formers. While vinegar is a secondary fermentation of alcohol, kombucha is a fermentation of sweetened tea.
The mechanics of that show why this is a mixed community. While vinegar formers like Acetobacter can work with alcohol, delivering them straight to a sugary medium with no middle stage may or may not yield the desired results. The SCOBY helpfully includes a range of bacteria and yeasts. Those transform the sugars into small amounts of alcohol that the various vinegar bugs then convert into a variety of organic acids.
I’ll have a lengthier post up soon about the organisms that tend to comprise kombucha and more about it as a composite organisms, but for now, let’s just make some!
How To Grow Your Own Kombucha SCOBY
Kombucha is widely available in grocery stores, and this how-to assumes you have access to a bottle of store bought. If not, you may need to hit Amazon or join a fermentation or kombucha group on Facebook (my favorite is called Wild Fermentation Uncensored) and ask for someone to send you one. Most people do so for the cost of shipping, and you’ll receive the pellicle floating in a quantity of starter tea.
For our purposes, we’re going to treat the bottle of kombucha you just ran out and bought as your starter tea. It should be live and unpasteurized and stored in a cooler at the store. I’m a Georgia girl, and while exploring our shiny new Kroger I stumbled upon some locally produced booch and couldn’t resist.
Oh, look at my cat in the background. Anyway, the ideal kombucha to use is unflavored, so I knew there was a possibility that this delicious Lavender-Lemon kombucha wouldn’t work out, but I gave it a shot anyway. It’s so easy. I took a small jar and poured an ounce or two of kombucha into it. I covered it with a paper towel and a rubber band (fruit flies love this stuff), and set it aside. It’s July in Atlanta, so our temperatures are ideal for powering up the cellulose makers in the mix. In the winter, this process may take weeks or longer, or may not happen at all, but this time around, I had a SCOBY forming within a few days.
I drank the rest of the bottle over ice, naturally.
Basically, I kicked this off at the end of one week and then transferred it into two cups of sweet tea in the middle of the next week, pellicle and all. The most important aspect of kombucha brewing isn’t the pellicle/SCOBY, though that’s what everyone raves about. Transferring the active liquid, in an appropriate quantity, is what inoculates your next batch of tea with the live organisms that make kombucha.
I used several tea bags and a couple of tablespoons of sugar for the two-cup transfer, pouring all of the smaller jar carefully into it once it had cooled to room temperature.
Again, cover with a breathable lid. Oxygen is key for the vinegar formers (although maybe not for the other common vinegar cousin, Jun), so make sure to use a good, tightly woven lid that will keep fruit flies out but let lots of oxygen in. Paper towels, kitchen towels, and coffee filters are all great options. Avoid cheesecloth, which is too loosely-woven to do a good job at this. Fruit flies are sneaky. Do not underestimate them.
I figured it would be another week before I had good growth at this stage, but nope. Three days later, this was waiting for me when I checked on it:
Last night, I finally sampled the brew beneath and transferred a starter quantity to a full quart of sweet tea. I used a quarter cup of sugar and four tea bags for a good stiff beverage. Most, but not all, of the sugar in the brew will be converted into acids. I don’t drink this stuff every day because of the sugar, but it’s a great treat.
And how does it compare to Jun, kombucha’s eccentric sibling? They’re quite different, to my taste. Jun is earthy and mellow and retains a hint of honey sweetness at the end. Kombucha is sharper and more up front, with flavors verging toward fruits and acidity.
So there it is, how to grow your own kombucha SCOBY at home. It’s a very simple process, and in summer temps, very quick.