Chocolate was first produced by the ancients as a by-product of beer, suggests a new archaeological study. And evidence from drinking vessels left by the Mesoamericans who developed chocolate suggests that the source of chocolate, cacao, was first used 500 years earlier than thought.

Mesoamericans – who flourished in central America before it was colonised by the Spanish – developed chocolate as a by-product of fermenting cacao fruit to make a beer-like drink called chicha still brewed by South American tribal people.

Unsweetened chocolate drinks became a central element of Mesoamerican cultures including the Aztecs, from whom Europeans learned of chocolate in the 16th century.

Chocolate's unique flavour develops only when the watery pulp of raw cacao fruit and seeds are fermented together, colouring the seeds purple. Grinding the seeds yields the chocolate.