Chocolate has been consumed in various guises for many centuries by diverse cultures. In 18 July Nature, Jeffrey Hurst and colleagues at the Hershey Foods Technical Center, Pennsylvania, show that the Mayans were consuming chocolate (Theobroma cacao) as early as 600 BC — almost a millennium earlier than previously thought (Nature 2002, 418:289-290).

Hurst et al. used high-performance liquid chromatography coupled with atmospheric-pressure chemical-ionization mass spectrophotometry to analyze samples taken from the inside of 14 ceramic vessels recovered from a series of burial sites at Colha in northern Belize. Using this technique they identified samples with a characteristic theobromine spike: T. cacao is the only Mesoamerican plant to contain theobromine.

The vessels, which are spouted rather like earthenware teapots, may have been used to pour cocoa mixture from one vessel to another to generate a froth — reputedly the Mayans' favourite part of...