At a recent potluck, a friend presented her offering—a pitcher of sloshing, deep-burgundy-hued liquid with chunks of fruit bobbing throughout—and challenged the group to guess what it was. “It’s not sangria?” someone ventured. “Try again,” she replied. When we remained stumped, she finally divulged the drink’s name—chicha morada—and its surprising contents: “It’s made with purple corn!”

The drink’s quite popular at Houston Peruvian restaurants like La Guitarra con Sazon in West Oaks. “I love it,” says Roxana Ortega, whose family owns the restaurant, adding that she especially enjoyed the stuff while pregnant. “I think my baby loved it, too. It’s refreshing.”

The drink dates back centuries, to the Incan tribes who originally occupied the South American country. Cobs of dried purple corn grown in the Andes—maíz morado—are simmered in water along with pineapple rinds, sticks of cinnamon and whole cloves until the liquid turns almost black. The mixture is then strained, blended with sugar and dosed with lime juice before fermenting overnight.

Though Ortega says Guitarra’s version, made from a family recipe, holds back on the sugar, it still packs an intensely sweet punch, making it the perfect base for the restaurant’s chicha sour, a classic Pisco sour amped up with the purple drink. Either beverage, by the way, makes a fine accompaniment to the restaurant’s menu of authentic Andes-style dishes such as lomo saltado, ceviche and mazamorra morada, a South American pudding made from the drink and served with berries.

Keen to make a batch of chicha morada at home? It’s simple enough, though finding purple corn can be tricky, even in Houston. The two Fiesta Mart locations on Bellaire Boulevard are your best bet.