This finding makes it the oldest know evidence of wine-making in the world, at 6000 BC in the Neolithic period. However, these traces dated back from 5400 to 5000 BC, also in the Neolithic period. Pottery fragments of ceramic jars recovered from the sites were collected and subsequently analyzed by scientists at the University of Pennsylvania to ascertain the nature of the residue preserved inside for several millennia.
The fragments of ceramic casks, some decorated with grape motifs and able to hold up to 80 gallons (300 liters), were found at two archeological sites called Gadachrili Gora and Shulaveris Gora, about 30 miles (50 kilometers) south of the Georgian capital Tbilisi.
"We believe this is the oldest example of the domestication of a wild-growing Eurasian grapevine exclusively for the production of wine", said Stephen Batiuk, co-author of the study from the University of Toronto.
The results, published in the Proceeding of the National Academy of Sciences, reveal that for eight of the fragments, including the two previously unearthed, the team found traces of tartaric acid - a substance found in grapes in large quantities. "The grapes are crushed and the fruit, stems and seeds are all fermented together", he told the BBC.
Pottery from a site in Georgia has tested positive for traces of wine.
The team of researchers hailed from the United States, Canada, Denmark, France, Italy, Israel, and Georgia. Also, they started creating tools out of stone and pottery out of clay.
Georgia, which has a long heritage of winemaking, is positioned at a crossroads between Western Asia and Eastern Europe, and the grape identified in jar fragments excavated from two Neolithic-era villages is Vitis vinifera - aka the "Eurasian grapevine", from which almost all kinds of modern wine originate.
The researchers say this chemical evidence is a snapshot of early human civilisation toward the end of the Stone Age, as it encountered new environments and made the best use of whatever resources found there - which in this case included cultivating the beginnings of all modern wine. So in many ways, this discovery brings my co-director Andrew Graham and I full circle back to the work of our professor Cuyler, who also provided some of the fundamental theories of the origins of agriculture in the Near East. This was the moment when humans started involving in agricultural activities such as plant-growing and animal domestication.
"The horticultural potential of the south Caucasus was bound to lead to the domestication of many new and different species, and innovative "secondary" products were bound to emerge".
One question still boggles the mind though: How did earlier civilisations produce their wine? The research suggests that one of the primary adaptations of the Neolithic way of life, as it spread to Caucasia (the area between the Black Sea and the Caspian Sea), was viniculture.
The domestication of the grape apparently led eventually led to the emergence of a wine culture in the region.
Batiuk thinks that the drinking and offering of wine played an important role in many aspects of life in the ancient Georgian society from medical practice, to celebrations of births and deaths and everyday meals.
While there are thousands of cultivars of wine around the world, nearly all derive from just one species of grape, with the Eurasian grape the only species ever domesticated.
"The Eurasian grapevine that now accounts for 99.9 percent of the wine made in the world today, has its roots in Caucasia", Batiuk said. Many designs are available.