Humanity’s love affair with chocolate began at least 500 years earlier than was thought previously, scientists have discovered.

Chemical residues found in pottery vessels from what is now Honduras have revealed that the ancient peoples of Central America were drinking chocolate beverages as long ago as 1150BC, probably to celebrate occasions such as births and weddings. The evidence suggests that they were alcoholic drinks made from fermented pulp of cacao fruit.

The frothy, chocolate-flavoured drink made from cacao seeds that is known to have been important in the culture of the Aztecs and the Maya did not emerge until later. The findings, from a team led by John Henderson, Professor of Anthropology at Cornell University in New York State, push back the origins of chocolate consumption by at least half a millennium. The earliest previous evidence was dated at about 600BC. Professor Henderson said it was likely that the distinctive taste of chocolate was stumbled upon by ancient brewers fermenting cacao pulp to make a kind of beer known later to the Spanish as chicha.

“In the course of beer brewing, you discover that if you ferment the seeds of the plant you get this chocolate taste,” he said. “It may be that the roots of the modern chocolate industry can be traced back to this primitive fermented drink.” The study, published in the journal Proceedings of the National Academy of Sciences, examined pottery from Puerto Escondido, in the Ulna Valley of Honduras, for traces of a chemical known as theobromine. This occurs only in the cacao plant, which is native to Central and South America, and from which chocolate is made.

Of 13 pottery samples, 11 tested positive for theobromine and/or caffeine, indicating the presence of chocolate. The pottery vessels are in a range of styles, which may indicate that they were traded among communities and perhaps that they were used in ceremonies to promote ties between them.

“These vessels were designed for pouring and drinking liquids; they are comparable to vessels in which cacao was served and consumed later in Mesoamerica,” Professor Henderson said. “We conclude that the early suites of vessels reflect the early history of cacao serving and drinking in ceremonies that took place at celebrations of marriages, births and other occasions.” The cacao bean went on to become an important element of culture across Mesoamerica – the region that includes Central America and modern Mexico. It was important to the Mayan and Aztec civilisations, and was even used as a form of currency. The Maya had a god of chocolate.

Studies of Mayan pots from more recent periods, along with contemporary accounts by Spanish conquistadors, indicate that the liquid chocolate was brewed in vessels and frothed to produce a foam, which the Maya and Aztecs considered the most delectable part. The froth was created using the spouts, through which a chef would blow air as the drink was poured from one vessel into another.

At the time of the Spanish Conquest in the 16th century, chocolate paste was mixed with ingredients such as water, maize, chilli and honey to create a variety of drinks, most of them extremely bitter. The idea of mixing it with sugar emerged in Spain in the 17th century, and chocolate in its solid form did not materialise until the 19th century.

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