Chemical evidence for the persistence of wine production and trade in Early Medieval Islamic Sicily

Abstract

Although wine was unquestionably one of the most important commodities traded in the Mediterranean during the Roman Empire, less is known about wine commerce after its fall and whether the trade continued in regions under Islamic control. To investigate, here we undertook systematic analysis of grapevine products in archaeological ceramics, encompassing the chemical analysis of 109 transport amphorae from the fifth to the eleventh centuries, as well as numerous control samples. By quantifying tartaric acid in relation to malic acid, we were able to distinguish grapevines from other fruit-based products with a high degree of confidence. Using these quantitative criteria, we show beyond doubt that wine continued to be traded through Sicily during the Islamic period. Wine was supplied locally within Sicily but also exported from Palermo to ports under Christian control. Such direct evidence supports the notion that Sicilian merchants continued to capitalize on profitable Mediterranean trade networks during the Islamic period, including the trade in products prohibited by the Islamic hadiths, and that the relationship between wine and the rise of Islam was far from straightforward.

New insights into early medieval Islamic cuisine: Organic residue analysis of pottery from rural and urban Sicily

“…When present, high oleic to stearic acid ratios (rare in archaeological samples) can indicate plant oils, alongside palmitic acid as a major constituent and sometimes unsaturated C 18:2 [68,69]. Short chain carboxylic acids (fumaric, succinic, malic, and tartaric) can be used to indicate the presence of fruit products [17,29]. The presence of alkylresorcinols can be used to identify cereals (wheat, barley and rye) [70][71][72] and the presence broomcorn millet can be identified in archaeological ceramics by the presence miliacin (olean-18-en-3β-ol methyl ether) [73,74].…”

“…Small organic acids, which are relatively insoluble in organic solvents were extracted from > 50% of the samples, using an acid butylation extraction developed by Garnier and Valamoti (2016) [17,29,85]. Malic and tartaric acids were identified, in variable amounts, in 97% and 70% of them, respectively.…”

“…Fumaric, maleic, malonic, and oxalic acids were detected less frequently, in 10%, 14%, 8% and 3% of the samples respectively. Although tartaric acid is one of the main acids in grapes and wine, its mere presence is not sufficient to formally identify these products in CLESP and Palermo vessels, since it also exists in other plants [17,85] and low amounts may be attributed to contamination from the burial environment [85]. Following the recommendations suggested by Drieu et al (2020) and (2021), we performed a quantification of tartaric acid to consider only vessels with a significant amount of tartaric acid, which is unlikely to be contamination [17,85].…”

“…Although tartaric acid is one of the main acids in grapes and wine, its mere presence is not sufficient to formally identify these products in CLESP and Palermo vessels, since it also exists in other plants [17,85] and low amounts may be attributed to contamination from the burial environment [85]. Following the recommendations suggested by Drieu et al (2020) and (2021), we performed a quantification of tartaric acid to consider only vessels with a significant amount of tartaric acid, which is unlikely to be contamination [17,85]. Comparison of the proportions of malic and tartaric acids in the pots was used to distinguish between the presence of grapevine products and that of other plants (Fig 7) [17,[85][86][87][88] (S3 Text).…”

“…Following the recommendations suggested by Drieu et al (2020) and (2021), we performed a quantification of tartaric acid to consider only vessels with a significant amount of tartaric acid, which is unlikely to be contamination [17,85]. Comparison of the proportions of malic and tartaric acids in the pots was used to distinguish between the presence of grapevine products and that of other plants (Fig 7) [17,[85][86][87][88] (S3 Text). Four vessels from CLESP and one sample from CSP produced a ratio of tartaric acid to the sum of tartaric and malic acids (%TA) of greater than 35%, characteristic of ripe grapes and their products (wine, juice, vinegar), as well as tamarind and some pomegranate cultivars [17,85] (Fig 7B ).…”