Although culture contact is a well-studied area of archaeological inquiry, complex ancient cross-cultural interactions can be challenging to discern. As zones of innovation in which boundaries are obscure, ancient frontiers offer ideal contexts to analyze the nuances of such interactions. To address the challenges of interpreting a multicultural frontier in the Moquegua Valley, southern Peru, we apply a practice-based approach using foodways to elucidate the complexity of culture contact between Wari-affiliated and Indigenous Huaracane communities during the Middle Horizon (AD 600–1000). Our findings indicate that after Wari colonization of the Moquegua frontier, the Huaracane community at Yahuay Alta began brewing chicha de molle, an alcoholic beverage associated with and central to Wari political and religious social structures. They did not, however, adopt the practice in a completely Wari fashion. Instead, we see Huaracane leaders brewed and served chicha de molle in ways that aligned with their own cultural practices. The material remains of chicha de molle production and consumption at Yahuay Alta should not be seen as a simple adoption of a nonlocal cultural practice by an Indigenous group, but instead an active manipulation of practice as part of frontier cultural negotiations and entanglements.