Beer is one of, if not the, world's oldest prepared beverages. More evidence of this has now come to light with researchers having used ancient relics to piece together a 5,000-year-old beer-making practice, providing what is claimed to be the earliest direct evidence of beer brewing in China.

Between 2004 and 2006, archaeologists recovered an assortment of artifacts from two pits at Mijiaya, a site in the north of China, dating back to 3,400-2,900 BCE. Among their haul were pottery vessels and stoves that were likely used to heat up grains for mashing.

A review of these findings by Stanford University professor Li Liu revealed that one of these vessels was actually shaped like a funnel, perfect for pouring beverages into storage containers.

So Liu and her colleague from Stanford, Jiajing Wang, set out for China to inspect the goods and scraped a yellowish residue from the inside of each vessel. Microscopic analysis of this residue revealed a pattern that indicated damage from preparing grains for the brewing process, something that involves their pitting and distortion.

The team also discovered signs of whole grains, an essential ingredient for beer-brewing. This evidence included husks from barley, broomcorn, millet and Job's tears, a grain native to South East Asia. To back up these findings, the team also found that the vessels appeared to be built for different stages of the beer-making process, providing the tools for brewing, filtration and storage.

"It makes a very convincing case that this was a beer-making facility," says Patrick McGovern, scientific director of the Biomolecular Archaeology Project at the University of Pennsylvania Museum in Philadelphia, who was not involved in the study.

The finding provides researchers with another clue in their efforts to trace the spread of fermented beverages around the globe. McGovern says the date of the pottery samples corresponds with other evidence of beer-brewing in Iran, Eqypt and Armenia from around the same time, and helps to fill a void between 7,000 BCE and the Shang dynasty in 1,500 BCE where more specialized fermented beverages began to appear.

"Beer was probably an important part of ritual feasting in ancient China," says Wang. "So it's possible that this finding of beer is associated with increased social complexity and changing events of the time."

The discovery also indicates that barley was initially brought to the Central Plain of China for beer-brewing, and only became a staple thereafter.

The research was published in the Proceedings of the National Academy of Sciences.

Source: PNAS