The excavations revealed a Neolithic village that was occupied in the second half of the sixth millennium BC where some of the oldest archaeological evidence of grape-based wine was discovered in the form of organic residue in a pottery jar.

The site was more thoroughly investigated between 1958 and 1968, when four excavation seasons took place as part of the larger Hasanlu Project conducted by the University of Pennsylvania Museum of Archaeology and Anthropology.

[3] The plain in which Hajji Firuz Tepe is located lies in the north-western part of the Zagros Mountains at an elevation of 1,300–1,350 metres (4,270–4,430 ft) amsl.

[6] The evidence for winemaking consisted of six 9-litre (2.4 US gal) jars that were embedded in the floor of what archeologists suspect was a kitchen area in a mudbrick building that was inhabited some time between 5400–5000 BC.

It is possible that the resin was used as a preservative, in a manner similar to the Greek wine Retsina still being produced today, suggesting that winemaking in Hajji Firuz Tepe was deliberately taking place over 7,000 years ago.

Additionally, archaeologists found clay stoppers, corresponding in size to the opening of the jars, nearby that also suggest a deliberate attempt at long term preservation and protection from air exposure.

[7] The Zagros Mountains, which separate modern day Iran from Armenia, Iraq and Turkey, is home to many wild species of grapevines in the Vitis family.

Several archaeological sites in the Zagros Mountains have uncovered similar findings as Hajji Firuz Tepe of jars containing tartaric deposits and wine residues.