Kombucha is an ancient and truly delicious tangy-sweet beverage that has many health benefits and has been passed down from generation to generation. It is the result of a fermentation process combining a Kombucha Mushroom, or 'Scoby' (Symbiotic Culture of Bacteria and Yeast) tea, sugar and water. Authentic kombucha scoby's are self-propagating making it a wonderful sustainable, enjoyable and economical beverage to do at home.
The Kombucha drink (minus the mushroom / scoby) is now available commercially at some health food stores. It's not as good as making the real thing at home because the companies need to halt the yeast fermentation (which creates the fizz) in order to bottle it commercially and prevent explosion. You are left with a drink that has high acid or suppressed culture.
Kombucha is one of the most simple at-home ferments. The mushroom (scoby), which looks somewhat like a pancake, simply converts a sugar-tea (Green, Black tea) solution over a period of 1-2 weeks into a health-promoting beverage that contains many organic acids, active enzymes, amino acids and polyphenols as well as many B-vitamins. When bottled it will also become fizzy and carbonated.