Kombucha is brewed using sugar, black or green tea, water, and a culture known as a SCOBY (symbiotic culture of bacteria and yeast), which is what allows it to ferment and also what gives it a slightly acidic flavor. There are several theories about when kombucha was discovered, but no way to prove any.

One theory states an alchemist gave the Manchurian emperor Qin She Huang kombucha, and the emperor became convinced it had life-extending properties. Over time, soldier from different countries drank the tea during times of war, and word about kombucha continued to spread.

Kombucha caught the attention of experts in the 1960s after a study in Switzerland uncovered its health benefits, but its popularity didn't take off until the 1990s after a small number of people started sharing their SCOBYs. Kombucha has become so popular in modern times that Slate once dubbed it the "most liberal product in America" — and its popularity is expected to continue growing.