Humans began exploiting cacao beans for alcohol before they started using them to make chocolate, according to new findings from a remote Honduran village that push the earliest known use of cacao back about 500 years.
Residue scraped from pottery vessels dating to 1400 BC to 1100 BC indicates that residents of the Ulua Valley fermented the sweet pulp of the chocolate plant to make an alcoholic drink well before they began grinding the bitter seeds and mixing them with honey and chiles to produce the equivalent of modern cocoa.
The consumption of fermented cacao is much more recent than the production of wine and beer, which date to about 5400 BC in Iran and 7000 BC in China.
The chocolate drinks, which had an alcohol content of about 5%, had a special role in feasting, entertaining and binding indigenous groups together, said archaeologist John S. Henderson of Cornell University, who led the team reporting the find Monday in the Proceedings of the National Academy of Sciences.
Henderson and archaeologist Rosemary A. Joyce of UC Berkeley have been excavating at Puerto Escondido in the alluvial valley of the Ulua River for more than a decade. The site has been called the Cradle of Chocolate because of its fertile soil and perfect conditions for cacao beans.
The beans were used as currency by the Olmecs and other peoples in the region for hundreds of years. Money literally "grew on trees," Henderson said.
Puerto Escondido has been continuously occupied since about 2000 BC by a largely agrarian people that shared a loose-knit society with the peoples around them, he said. The identity of the people who lived there in the second millennium BC is not clear, but they may have been precursors of the Olmec, whose civilization began to emerge around 1100 BC.
Before the current study, the oldest known use of cacao was marked by the discovery of a bottle containing traces of the material excavated from a grave in Colha in northern Belize. The bottle dated to 600 BC.
Archaeologist Patrick E. McGovern of the University of Pennsylvania Museum, who was involved in dating early uses of fermented beverages around the world, heard about Henderson and Joyce's efforts to date cacao use at Puerto Escondido and volunteered his services.
McGovern was able to extract traces of theobromine, the characteristic marker of Central American cacao, from the porous surfaces of pottery shards they sent him. "The results were astounding," he said. "Every vessel that he had chosen and was tested gave a positive signal for theobromine."
Although no traces of alcohol remain in the vessels, the pottery was of a type that is still used for alcoholic drinks. Pottery characteristically used for nonalcoholic chocolate drinks did not appear until a few hundred years later, the team said.
Henderson speculates that the story is not over yet and that they may find evidence of cacao use even earlier than 1500 BC.
"We're being conservative," he said. "I think it goes back much farther than that."