The Beer Archaeologist explains all at the Smithsonian:
... “Dr. Pat,” as he’s known at Dogfish Head, is the world’s foremost expert on ancient fermented beverages, and he cracks long-forgotten recipes with chemistry, scouring ancient kegs and bottles for residue samples to scrutinize in the lab. He has identified the world’s oldest known barley beer (from Iran’s Zagros Mountains, dating to 3400 B.C.), the oldest grape wine (also from the Zagros, circa 5400 B.C.) and the earliest known booze of any kind, a Neolithic grog from China’s Yellow River Valley brewed some 9,000 years ago....
