Wine and olive oil permeation in pitched and non-pitched ceramics: relation with results from archaeological amphorae from Sagalassos, Turkey

Pitch compounds are frequently identified inside archaeological ceramic vessels. As their presence might affect the permeation of oil or wine into the ceramic fabric, experiments were conducted in which the diffusion of lipids or polyphenols into pitched and non-pitched modern vessels was followed by chemical analysis. Results show that the polyphenols of wine can intrude into the ceramics even through a pitch layer. Consequently, the absence of polyphenols in archaeological sherds is not due to their inability to reach the ceramic matrix under the pitch layer. By contrast, a pitch layer is quite effective to avoid oil intrusion into the ceramic matrix. Thus, it seems logical that oil amphorae would have been coated with pitch at the inside prior to use. Experiments in which the pitched ceramic was simultaneously exposed to oil and wine, show that the wine makes the pitch more permeable for the lipid compounds. These experimental data are confronted with residue analysis results obtained on amphorae fragments excavated in Sagalassos, Turkey. Pitch and oil were frequently found together. Based on a polyphenol test, indications for wine storage could only be obtained for two vessels. Against this background, the possible uses of the Sagalassos amphorae are discussed, and the traditional association of pine pitch with wine storage in archaeological amphorae is critically assessed.