WASHINGTON (Reuters) - The chocolate enjoyed around the world today had its origins at least 3,100 years ago in Central America not as the sweet treat people now crave but as a celebratory beer-like beverage and status symbol, scientists said on Monday.

This pottery vessel from northern Honduras is of the same type and form as ones in which scientists found the earliest known evidence of the use of the cacao plant -- the source of chocolate. Image courtesy of PNAS/National Academy of Sciences. REUTERS/Handout

Researchers identified residue of a chemical compound that comes exclusively from the cacao plant -- the source of chocolate -- in pottery vessels dating from about 1100 BC in Puerto Escondido, Honduras.

This pushed back by at least 500 years the earliest documented use of cacao, an important luxury commodity in Mesoamerica before European invaders arrived and now the basis of the modern chocolate industry.

Cacao (pronounced cah-COW) seeds were used to make ceremonial beverages consumed by elites of the Aztecs and other civilizations, while also being used as a form of currency.

The Spanish conquistadors who shattered the Aztec empire in the 16th century were smitten with a chocolate beverage made from cacao seeds served in the palace of the emperor. However, this was not the form in which cacao had its beginnings.

“The earliest cacao beverages consumed at Puerto Escondido were likely produced by fermenting the sweet pulp surrounding the seeds,” the scientists wrote in the journal Proceedings of the National Academy of Sciences.

One of the researchers, anthropologist John Henderson of Cornell University in Ithaca, New York, said cacao beverages were being concocted far earlier than previously believed -- and it was a beer-like drink that started the chocolate craze.

“What we’re seeing in this early village is a very early stage in which serving cacao at fancy occasions is one of the strategies that upwardly mobile families are using to establish themselves, to accumulate social prestige,” Henderson said in a telephone interview.

“I think this is part of the process by which you eventually get stratified societies,” Henderson said.

The cacao brew consumed at the village of perhaps 200 to 300 people may have evolved into the chocolate beverage known from later in Mesoamerican history not by design but as “an accidental byproduct of some brewing,” Henderson said.

The chocolate enjoyed by later Mesoamerican civilizations like the Maya and Aztecs was made from ground cacao seeds with added seasonings, producing a spicy, frothy drink.

The Spanish brought cacao back to Europe in the 16th century. Many innovations occurred in the ensuing centuries, including the advent of solid chocolate treats.

The scientists used chemical analysis of residues extracted from pottery vessels from the Honduran site to determine that cacao had been used.

The style of the 10 small, elegant serving vessels suggests the cacao brew was served at important ceremonies perhaps to celebrate weddings and births, the scientists said.

Henderson said the first use of cacao may be earlier still by perhaps a couple of centuries. He said the scientists intend to test earlier pottery from the region for chemical proof.