Since the Formative times, maize is and has been a highly valued social commodity in the Andes, particularly in the form of a traditional beer called chicha. While chicha production is well attested in the archaeology and ethnohistory of Andean states, the emergence of maize symbolism in earlier societies has not been systematically addressed. In this study phytolith and starch grain analyses are used to trace production, processing, and consumption of maize at sites on the Taraco Peninsula of Bolivia and thus the entrance of maize into the region. We systematically examine the role of maize by addressing its rarity, use contexts, and preparation. The pattern of plant part representation and use suggest that maize was being consumed in the form of chicha at its earliest introduction to the Titicaca Basin (800–250 B.C.). Drinking of alcohol in ceremonial spaces embodies the process of commensality of public ceremony and the establishment of reciprocal relationships during the Formative period. These results demonstrate that contextual analysis of microbotanical remains has great potential to answer anthropological questions surrounding food, ritual, and identity.