Wine making's roots age in stained jar.

Last year, archaeological chemists at the University of Pennsylvania Museum in Philadelphia noticed a yellowish white blotch on the inner surface of a pottery fragment housed in their facility. Ancient wine residues usually cast a reddish hue, but on closer inspection of the substance, the scientists hit pay dirt-the oldest known evidence of wine making, dating to between 7,000 and 7,400 years ago.

"Analysis of this jar shows that wine containing a tree resin additive, used for preservation or to cover up unwanted flavors, was produced in the northern Zagros mountains of Iran 2 millennia earlier than previous evidence from the Near East [had indicated]," asserts study director Patrick E. McGovern. Prior findings had dated wine making to about 5,500 years ago (SN: 5/4/91, p. 279). Excavations more than a decade ago at Hajji Firuz Tepe, an ancient village where residents grew barley and raised cattle, yielded the pottery shard studied by McGovern's group as well as five similar vessels, all from the cooking room of a mud brick structure. Mary M. Voigt, an archaeologist at the College of William and Mary in Williamsburg, Va., led that dig. The site's age derives from a series of radiocarbon dates.

Chemical analyses of the telltale stain identified its principal component as the calcium salt of tartaric acid. Grapes are the only food known to contain large amounts of tartaric acid, McGovern says. The yellowish resin of the terebinth tree was also present. These trees grow throughout the Near East, and their resin was added to medicine and wine by many early societies, according to McGovern.

Tartaric acid and terebinth resin occur together in a large number of Near Eastern jars, including wine-bearing jugs from ancient Egypt, he adds. The 2.5-gallon Iranian container had a long, narrow neck, thick walls, and a stopper, all signs that it contained a liquid, argue McGovern and coworkers Donald L. Glusker and Lawrence J. Exner in the June 6 Nature. The addition of terebinth resin served in part to inhibit the growth of bacteria that convert wine to vinegar, the researchers assert. Terebinth, which can be distilled into turpentine, may also have masked any offensive flavors in the wine, they suggest. McGovern regards the use of terebinth as a preservative as a "profound development" that made possible shipping and trading of wine.