From artifacts and other evidence, scholars had already determined that beer was the favorite fermented beverage of the Sumerians, who lived mainly in the lower Tigris-Euphrates valley. Some of their art depicted people standing around a large vessel, drinking something out of it, presumably beer, with long straws.

One of the most common pictographs in Sumerian ruins is the sign for "beer," which shows linear markings within a jar. These markings are similar to the unusual crisscross pattern of incisions inside the vessel where the telltale beer residue was identified.

"It's chemical substantiation of what were archeological arguments before," Dr. Patrick E. McGovern, an archeological chemist at the University Museum of Archeology and Anthropology at the University of Pennsylvania, said in an interview yesterday.

Dr. McGovern conducted the analysis along with Dr. Rudolph H. Michel, an organic chemist at the museum. Virginia R. Badler, a graduate student at the University of Toronto, had noted the residue in the jug grooves while studying artifacts from Godin Tepe in the collections of the Royal Ontario Museum in Toronto. These researchers, who wrote the Nature report, were the same ones responsible for identifying the earliest known wine from red stains in other jars from the same site. 'A Lot of Serious Drinking'

Asked the meaning of finding both the earliest known wine and beer in the same room, Dr. McGovern replied, "I think a lot of serious drinking was going on there."