If you haven't tasted kombucha yet, you probably will soon. The sour-sweet, fizzy, fermented tea is becoming ubiquitous in trendy cafes, workplaces, and health food stores across America. Where did it come from, and how did it get so popular? And what in the world is the slimy, beige blob that produces it? From German POWs to Lindsey Lohan to a kombucha zoo at Tufts University, this episode explores the history and science of summer's hottest drink.

Kombucha's origins—like almost everything about the drink—are a combination of myth and mystery. According to Tufts University microbiologist Ben Wolfe, all we know is "it was originally produced in parts of China, as well as what is now Russia." Other countries, including Korea and Tibet, have their own kombucha creation stories. Though the exact date and location in which it was first brewed remains obscure, it seems clear that kombucha arose in the Far East, where tea has been popular for thousands of years.

That doesn't explain how kombucha traveled west. But, by translating a little-known paper published in the Deutscher Apotheker Verlag (a German scientific journal) in 1930, Gastropod managed to trace the arrival of the "Indian tea fungus," as the author called it, to Europe following World War I, when it was brought home by German POWs who had been held in Russia. Still, it wasn't until 1990s Los Angeles that kombucha became a commercial success in the U.S., fueled first by the AIDS epidemic, and later by a growing interest in probiotics and gut health.