What is kombucha?
Kombucha is a fermented drink. It is made by brewing tea with sugar and then letting a SCOBY (Symbiotic Culture of Bacteria and Yeast) ferment it. Fermenting means that the microbes will eat the sugar and in its turn produce other compounds that give the drink its unique flavor and properties. The microbes also produce CO2, which means they naturally carbonate the drink. In other words: the end result is a slightly sweet, slightly acidic fizzy drink filled with microbes that do wonders to your gut.
Where does it come from?
Kombucha is truly an ancestral drink, so it is not quite clear when it started being brewed. Our guess is that someone forgot their tea for too long and was brave enough to drink it afterwards - changing history forever!
Although our guess is as good as the next one, the official archives say that it probably originated in Manchuria (Northern China) or in what is now East Russia. It could have been brewed up to 200 years BC: it was cherished by the Tsin Dynasty because of its "detoxifying and energizing properties"(Jayabalan et al 2014).
And who are we to contradict the Tsin Dynasty?!
The kombucha SCOBY is a funny thing. First of all, you can actually see it (when the general premise of microbes is that they're microscopic right?). And to be really honest with you, it doesn't look great. Here's a visual:
Yes, it's slimy, it's amorphous; but it's great at its job of fermenting! You go SCOBY, we love you.
You can see the SCOBY as a consequence of the epic collaboration between bacteria and yeast. As part of their symbiotic relationship, bacteria release cellulose, which becomes a protective matrix where microbes can be embedded. So what you see and touch is cellulose filled with lovely bacteria and yeast. As poetic scientists have said before, a SCOBY is just like a city of microbes.
The fermentation process
Kombucha is very easily made: you'll just need to inherit a SCOBY from a fellow home brewer to get started. During the fermentation process, sucrose from sugar is converted into both cellulose and the acidic compounds that will give the flavor to the drink: acetid acid, lactic acid, gluconic acid, and glucuronic acid.
Details of the fermentation process, for all nerds out there like us (Villarreal-Soto et al., 2018)
So once the sugar has been fermented, and thus kombucha produced, the drink contains organic acid compounds (mentioned above), non-fermented sugar, vitamins (B1, B2, B6, B12, C), tea polyphenols, amino acids, minerals, and live kombucha culture.