Savory, sour and effervescent, kvass has been a subtly alcohol beverage enjoyed by Eastern Europeans for over a thousand years. Its most famous form is yeasty, malty bread kvass, made from fermented stale rye bread and, sometimes, herbs or fruit. But it can be made with nearly anything. There is Polish beet kvass (an earthy and tangy byproduct of fermenting beets for borscht), delicate Ukrainian lettuce kvass and even tea kvass.

In Russia, bread kvass was a staple of the peasant diet, customarily drunk chilled or used as a base for cold soups. Entranced by its folkloric past, the Soviets anointed it their answer to Coca-Cola and pumped up industrial production. The market is now dominated by commercial producers, though many brands—often sugary-sweet and made with soda syrup—have little in common with the genuine article.

In the U.S., kvass is now being made by a handful of small producers, as well as restaurants and bartenders. While kvass’s intensely savory and tangy flavor profile might keep it from making a real play at the mainstream, it’s increasingly being used in cocktails—from riffs on picklebacks at Bar Tartine to brandy cocktails at Portland’s Kachka.