Ellen Phiddian
Cosmos science journalist
Chemical residue from grapes has been found inside medieval containers from Islamic Sicily, suggesting there was wine production on the island.
A study, published today in the Proceedings of the National Academy of Science, examined amphorae from the 9th to 11thcenturies, and found evidence that the containers had been used to store wine.
The researchers extracted and measured organic compounds from the interiors of the medieval jars. They also filled some replica pots with commercial wine and buried them for twelve months to let the wine degrade. They then compared the residue from the modern jars to the medieval containers.
Most of the organic compounds that appear in wine also appear in fresh fruit and berries, so it can be difficult to tell what the original source of the compounds was. The researchers solved this problem by comparing the ratio of different compounds in the jars – specifically, the ratio of tartaric acid to malic acid. The acid ratio in wine is very different to the ratio in fresh fruit.
They found that the acid ratios in the amphorae matched the ratios from the experimental, wine-containing jars. This means that the medieval amphorae very likely had wine in them.
“We had to develop some new chemical analysis techniques in order to determine that it was grape traces we were seeing and not some other type of fruit,” says Léa Drieu, a postdoctoral research assistant at the University of York, UK. “But the tell-tale organic residues found in the amphorae in Sicily, Palermo and elsewhere showed the content was almost certainly wine.”
Amphorae were traditionally used for transporting wine across the ancient world, but it’s unusual to see evidence of winemaking and trade in an Islamic community. Prior to Islamic occupation in the 9th century, wine was traded in Sicily but not widely produced. This research suggests the Islamic community began to produce and export wine, to further boost their agricultural trade.
“Alcohol did not – and still does not – play a major role in the cultural life of Islamic society, so we were very interested in the question of how this medieval community had thrived in a wine-dominated region,” says Martin Carver, a professor from the University of York’s Department of Archaeology.
“Not only did they thrive, but built a solid economic foundation that gave them a very promising future, with the wine industry one of the core elements of their success.”
There’s no indication that members of the community drank the wine they made. There may never be enough evidence to determine the beverage of choice for Islamic Sicily. Historical records from the period are limited, and alcohol degrades quickly once consumed, making it difficult to study on an archaeological scale.
“The equation between the transportation of wine and the rise of Islam is likely to be far from simple,” says the paper.
Whether or not it was drunk in Sicily, the wine was certainly being bought and consumed elsewhere. The amphorae were also found in Sardinia and Pisa.
“Now that we have a quick and reliable test for grape products in ceramic containers, it will be interesting to investigate the deeper history, and even prehistory, of wine production and trade in the Mediterranean,” says Oliver Craig, a professor at the BioArCh centre where the analysis was done.