Chinese villagers could have been sharing a beer about 5000 years ago, according to researchers.

Residue on pottery from an archaeological site has revealed the earliest evidence of beer brewing in ancient China, showing barley may have been used for beer long before it was grown for food.

The artefacts show people of the era had already mastered an “advanced beer brewing technique” containing elements from East and West, according to a study in the Proceedings of the National Academy of Sciences.

• Bricks and slaughter: Lego’s new ‘arms race’
• Darth by Darthwest: the mashup you’ve been looking for
• How Uber is able to exploit our desperation

Yellowish residue gleaned from pottery funnels and wide-mouthed pots show traces of ingredients that had been fermented together – broomcorn millet, barley, a chewy grain known as Job’s tears, and tubers.

“The discovery of barley is a surprise,” lead author Jiajing Wang of Stanford University said, saying it is the earliest known sign of barley in archaeological materials from China.

“This beer recipe indicates a mix of Chinese and Western traditions – barley from the West; millet, Job’s tears and tubers from China.”

However, it is impossible to know exactly how the beer tasted, researchers said, because they do not know the ingredients’ exact proportion.

“My guess is that the beer might have tasted a bit sour and a bit sweet,” Ms Wang said.

“Sour comes from fermented cereal grains, sweet from tubers.”

The discovery indicates barley made its way to China some 1000 years earlier than previously believed.

The archaeological site at Mijiaya, near a tributary of the Wei River in northern China, includes two pits dating to around 3400-2900 BC.

It contains artefacts pointing to beer brewing, filtration and underground storage, as well as stoves that may have been used to heat and mash grains.

-with agencies