Ancient drinker of the fermented beverage chicha

INCAN

This South American civilization thrived in the Andes Mountains and was known for their advanced stonework—try pairing their name with a popular corn-based drink.

This clue points to the Inca, the ancient South American civilization known for brewing and drinking chicha, a traditional fermented corn beverage. The word "drinker" hints at the people associated with the drink rather than the drink itself. "Incan" is the adjectival form referring to the Inca Empire, fitting the crossword’s answer format.