Black tea is fermented with bacteria, yeast and sugar to create Kombucha. A scoby, or symbiotic colony of bacteria and yeast, is produced during the fermentation process. Probiotics, acetic acid and antioxidants are all in kombucha after fermentation, and they can all have health benefits.
Studies on animals and in the laboratory reveal that kombucha can improve blood sugar levels in diabetics, cholesterol levels and the immune system. However, the reported health benefits in humans are mostly anecdotal. Since there is a significant chance that your homemade kombucha may be contaminated with dangerous microorganisms, it is not recommended. However, there are several commercially available types that do not have the same risk.