(image from unrelated story, here - which is worth browsing through as well)
WIRED: 2,550-Year-Old Celtic Beer Recipe Resurrected
Early Celtic rulers of a community in what’s now southwestern Germany liked to party, staging elaborate feasts in a ceremonial center. The business side of their revelries was located in a nearby brewery capable of turning out large quantities of a beer with a dark, smoky, slightly sour taste, new evidence suggests.
Six specially constructed ditches previously excavated at Eberdingen-Hochdorf a 2,550-year-old Celtic settlement, were used to make high-quality barley malt, a key beer ingredient, says archaeobotanist Hans-Peter Stika of the University of Hohenheim in Stuttgart. Thousands of charred barley grains unearthed in the ditches about a decade ago came from a large malt-making enterprise, Stika reports in a paper published online January 4 in Archaeological and Anthropological Sciences.
Stika bases that conclusion on a close resemblance of the ancient grains to barley malt that he made by reproducing several methods that Iron Age folk might have used. He also compared the ancient grains to malt produced in modern facilities. Upon confirming the presence of malt at the Celtic site, Stika reconstructed malt-making techniques there to determine how they must have affected beer taste.
The oldest known beer residue and brewing facilities date to 5,500 years ago in the Middle East, but archaeological clues to beer’s history are rare (SN: 10/2/04, p. 216).