Kombucha

Definition

Kombucha is made by fermenting sweetened tea with a SCOBY, a symbiotic culture of bacteria and yeast. The culture forms a rubbery cellulose mat on the surface of the liquid. Yeasts convert sugar to alcohol and carbon dioxide, and acetic acid bacteria, mainly Komagataeibacter species, convert much of the alcohol to acetic acid and other organic acids. The result is sour, slightly sweet and lightly carbonated. The drink is recorded in Russia and eastern Europe in the early twentieth century, and its earlier origin is uncertain; stories placing it in ancient China are not documented. It became a commercial product in North America in the 1990s and 2000s. Black and green tea are the usual bases because they supply nitrogen and other nutrients the culture needs. A batch is usually fermented for 7 to 14 days at room temperature, reaching a pH of roughly 2.5 to 3.5. Many producers then bottle it with fruit or juice for a second fermentation that builds fizz. Kombucha keeps some caffeine from the tea and contains a small amount of alcohol, usually below 0.5 percent, though home batches and long ferments can run higher.