Beer recipes change over time. Hops, for example—which give many a modern brewski its bitter, citrusy flavor—are a relatively recent addition to the beverage, first mentioned in reference to brewing in the ninth century. Now, researchers have found a surprising ingredient in residue from 5000-year-old beer brewing equipment. While excavating two pits at a site in the central plains of China, scientists discovered pottery fragments from pots, funnels, amphorae, and stoves (stove fragment pictured). The different shapes of the containers suggest they were used to brew, filter, and store beer—they may be ancient “beer-making toolkits,” and the earliest direct evidence of beer brewing in China, the researchers report online today in the Proceedings of the National Academy of Sciences. To test that hypothesis, the team examined the yellowish, dried dregs inside the vessels. About a third of the starch grains they found were pitted, swollen, folded, or distorted—types of mangling that can occur during the malting and mashing needed to make beer. The majority of the grains—about 80%—were from cereal crops like millet and barley, and about 10% were bits of tubers, including yam and lily, which would have sweetened the brew, the scientists say. Barley was an unexpected find: The crop was domesticated in western Eurasia and didn’t become a staple food in central China until about 2000 years ago, according to the researchers. Based on that timing, they suggest barley may have arrived in the region not as food, but as fodder for brewing beer.