Archeologists have unearthed the oldest wine-making facility ever found, using biochemical techniques to identify a dry red vintage made about 6,000 years ago in what is now southern Armenia.

The excavation paints a picture of a complex society where mourners tasted a special vintage made at a caveside cemetery, the researchers reported on Tuesday in the Journal of Archaeological Science.

"This is the world's oldest known installation to make wine," Gregory Areshian of the University of California Los Angeles, who helped lead the study, said in a telephone interview.

Carbon dating showed a desiccated grape vine found near a wine press was grown around 4000 BC, his team reported.

This makes it 1,000 years older than any other wine-making facility discovered, the team from Armenia, the United States and Ireland reported.

The team found the world's oldest leather shoe, about 5,500 years old, at the same cave complex last year.

The wine press would have held a few gallons of juice and crushed grapes, likely working with the time-honored technique of barefoot stomping, Areshian said.

"This was a relatively small installation related to the ritual inside the cave. For daily consumption they would have had much larger wine presses in the regular settlement," said Areshian, who was deputy prime minister in the first government of the independent Republic of Armenia in 1991.

Chemical traces point to grape juice and, given the lack of refrigeration, the juice would certainly have been fermented into wine, Areshian said.

"We also know that still, in the villages in the vicinity, the culture of wine is very old and traditional," he said.

The rich red wines produced there are merlots and cabernet sauvignons, he said.

The expedition, paid for in part by the National Geographic Society, also uncovered copper processing equipment. Areshian said the team would detail those findings later.

The cave complex, known as Areni-1, is in the Little Caucasus Mountains near Armenia's southern border with Iran.

The press itself is a shallow clay basin about three feet (one meter) in diameter, surrounded by grape seeds and dried-out grape vines.

The team found grave mounds nearby and obsidian tools -- indicating some complicated trade was going on. The closest source of obsidian, a black glassy mineral, is 35 to 45 miles away, a three-day walk, Areshian said.

"We can say that this was a quite complex society formed by multiple communities," he said.