A brewery kit for beer-making dating back 5,000 years has been discovered among artefacts from an archaeological site in northern China.
Yellowish remnants found inside wide-mouthed pots, funnels and amphora jars suggest that the vessels were used for making, filtering and storing beer, say scientists.
Analysis of the residues revealed evidence of starchy plants including broomcorn millets, barley and "Job's tears", a tall grain-bearing grass.
Some starch grains bore marks that could have been left by malting and mashing.
Further evidence was the presence of oxalate, a by-product of beer brewing, in some of the vessels.
The "brewery" was uncovered in two pits at Mijaya, near a tributary of the Wei River, dating as far back as 2,900 BC.
Writing in the journal Proceedings of the National Academy of Sciences (PNAS), the team led by Dr Jiajing Wang, from Stanford University in the US, concluded: "The results indicate that people in China established advanced beer-brewing technology by using specialised tools and creating favourable fermentation conditions around 5,000 years ago.
"Our findings imply that early beer making may have motivated the initial translocation of barley from the Western Eurasia into the Central Plain of China before the crop became a part of agricultural subsistence in the region 3,000 years later."