Kombucha is a refreshing, fermented drink that is made from sweetened black or green tea using a kombucha culture. This culture consists of some ready-fermented Kombucha (the liquid) and a so-called Kombucha scoby.
SCOBY is an abbreviation of "Symbiotic Culture Of Bacteria and Yeast". The scoby usually looks like a round disc. In German, it is often called a tea fungus, even though this is not quite correct. Kombucha is not a mushroom at all, but a small ecosystem that consists of various bacteria and yeasts that live together in symbiosis. The scoby gets its gelatinous structure from some of its bacteria that constantly weave together a new layer of cellulose on the liquid surface of the kombucha. That is why the scoby always has the shape of the vessel in which you ferment your kombucha and that is why it always forms a new layer of scoby on top of the old. While the kombucha is fermenting, the sugar and also some components from the tea are being metabolized by the yeasts and bacteria. In the process, the yeasts first produce alcohol from the sugar, which is then metabolized by the bacteria (mainly acetic acid bacteria) into acetic acid and other organic substances. This also produces some carbon dioxide, various B vitamins and lots of enzymes.
After about 7-10 days of fermentation you can then make a delicious, refreshing and extremely healthy drink full of probiotics - your own homemade kombucha!
It's a great alternative to unhealthy soft drinks, and it's easy and inexpensive to make right in your kitchen.