Identifying wine in archaeological pottery? A case study from the Late Antique and Early Medieval Sicily

Abstract

International audienceWine, an emblematic fermented commodity of the Mediterranean, remains difficult to identify in archaeology, despite being the focus of many investigations (amphora morphology and provenance, aDNA, carpological studies, etc.). While the search for wine biomarkers (particularly tartaric acid) began with the very first attempts of organic residue analysis of archaeological pottery, a wide range of methods have been used with little consensus.In order to study the wine trade in Sicily between Late Antiquity and the Early Middle Ages, and the possible impact of the successive Byzantine and Arab conquests, it was necessary to set up a rigorous methodology, which optimises extraction yields and avoids false positives. The comparative analysis of authentic references and archaeological samples through different approaches revealed the high efficiency of butylation under acidic conditions to extract tartaric acid. The difficulty in understanding the natural origin of other small acids makes their presence in archaeological ceramics misleading. The specificity of tartaric acid in terms of its natural origin was investigated using a context where the grape is not attested (Russian prehistoric potsherds). Analyses showed that in the absence of other archaeological or historical evidence, tartaric acid could only be interpreted as a fruit biomarker. Finally, the analysis of control samples (cooking pots, handles, tiles, sediments) and a large corpus of amphorae produced and imported in Sicily from the 5th to 11th century AD demonstrated the need for tartaric acid quantification and the use of a limit of interpretationto avoid false positives. Based on these methodological developments and the selection of morphologically and petrographicallywell-characterised vessels, it has been possible to demonstrate an unexpected continuity of the exploitation and trade of grapevineproducts from the Late Roman period to the Early Middle Ages in Sicily, in spite of the succession of regimes that have dominatedthe island