Pulque, the alcoholic beverage of pre-Columbian highland Mesoamerica is the fermented derivative of aguamiel, the juice or sap of the agave known as agave pulquero—principally Agave salmiana. Aguamiel is a sweet, somewhat heavy juice that collects in a scraped out basin in the heart of the agave pulquero and, unless refrigerated, rapidly ferments into the alcoholic pulque. The agents of fermentation are ambient and plant-colonizing bacteria and yeasts. Fresh pulque is a frothy, cloudy brew with a slightly sour taste, usually containing around 2 percent alcohol or somewhat higher, meaning it can be drunk in large quantities without intoxicating the imbiber. Although it is a nutritious drink, consumption was condemned by Spaniards in varying degrees during the Colonial Period. Its popularity in contemporary southern Mexico is increasing after more than a century of persecution and public disparagement. Pulque figures prominently in pre- and post-Columbian Mesoamerican history.
Production of tequila and mezcal is completely different from production of pulque. The former are distilled from the pressed juice (tepache) of macerated and roasted hearts of certain agaves. The juice is fermented in vats for several days, then heated in a still, evaporated, and condensed. Tequila, by law is made from A. tequilana, and mezcal by custom is made primarily from A. angustifolia. Both these distillates contain about 40 percent alcohol. Pulque is a naturally occurring product consumed by native peoples for at least two millennia. Tequila and mezcal are industrial products derived from processes introduced into the Americas by Europeans.