Life was tough at Teotihuacan. The biggest city in pre-Columbian Mesoamerica depended on maize and beans to keep its 100,000 residents fed, but the unfortunate combination of low rainfall and high altitude in the highlands of central Mexico led to crop failure all too often. So how did Teotihuacanos avoid starving in lean times? By drinking fermented agave sap, of course. Pulque—a distinctly mucus-y beverage made by extracting sap from the heart of a mature agave plant and letting it sit around for a few days—was known to have been made and consumed by the Aztecs around the time of the Spanish conquest in 1521 C.E. But archaeologists weren’t sure if the drink had also been popular in Teotihuacan, an earlier and culturally distinct city in central Mexico that thrived between 150 B.C.E. and 650 C.E. (Its ruins are pictured above.) Excavations at the city had turned up several ceramic vessels waterproofed with tree resin that would have been perfect for storing pulque, however. When their surfaces were chemically examined, 14 of the vessels tested positive for byproducts of a bacterium called Zymomonas mobilis, a key ingredient in pulque production, researchers report online today in the Proceedings of the National Academy of Sciences. Dating to 200 to 550 C.E., this is the earliest evidence for the production of alcohol in Mesoamerica. But pulque probably wasn’t just used for getting tipsy, the researchers propose. The drink is probiotic, nutritious, and so viscous that just one glass makes you feel full—all traits that could have made pulque an important dietary supplement for Teotihuacanos, especially in years with poor harvests.