In the current issue of the journal Analytical Chemistry, researchers from the University of Barcelona describe a novel approach to pinpointing what those wine jars held. The presence of tartaric acid, a compound with few natural sources other than grapes, is used to identify wine in ancient residues but does not discriminate between red and white grapes. Maria Rosa Guasch-Jane and her colleagues thus tested part of a wine jar recovered from Tutankhamen¿s tomb for the chemical that imparts color to red wine, malvidin-3-glucoside. Direct testing for the substance is not feasible, so the scientists instead exposed the sample to a basic solution that causes malvidin to break down into syringic acid, a chemical that can be detected. "This method led us for the first time not only to identify the presence of wine but also to reveal the red grape origin of the wine contained in a jar belonging to the tomb of King Tutankhamen," the team writes.
The investigators plan to utilize their new technique for more extensive studies on other archaeological samples. Now, they note, "we have the key to uncovering the origins of enology, as well as opening future investigations into the color of ancient wines."