Finding in northern Iraq adds to pictorial and written records.What could be better than a cold one in the desert? For an archaeologist, how about finding chemical evidence that people in that desert enjoyed the same brew some 2,500 years ago?
Achaeologists have detected beer residues in clay cups from two and a half millennia ago, buried beneath the sand in northern Iraq.
Granted, it’s not the first evidence of beer in the ancient world: we have pictorial representations of imbibing, as well as references in old accounting texts describing beer given as rations. In fact, the Epic of Gilgamesh, a Mesopotamian poem considered the oldest surviving work of literature, describes the civilizing effect seven jugs of beer had on a wild man.
And a physical trace of beer from the late fourth millennium BC was found in present-day Iran.
But in a new study, published in the Journal of Archaeological Science, Elsa Perruchini, a PhD archaeology at the University of Glasgow, examined the chemicals present in the residues clinging to the clay of old cups and jars.
“What Elsa has demonstrated is the chemical signature of fermentation in the vessels that also contains the chemical signatures consistent with barley,” said coauthor Claudia Glatz, a senior lecturer in archaeology at the University of Glasgow.
Key to the discovery was doing chemical tests in the field rather than bringing artifacts to a lab. This avoided handling of the artifacts, which often leaves residue from the hands of humans and corrupts the chemical evidence. One residue that is especially troubling is sunscreen.
As Smithsonian magazine explained:
Perruchini then analyzed the distinct compounds of the residues using gas chromatography, a technique that separates the various compounds present in a mixture. Gas chromatography had not been used in archaeology to examine a collection of compounds to identify something like beer, and the method allowed her to get very specific in her analysis. The team could ignore any contemporary chemicals, while an analysis of soil samples taken from outside the clay vessels allowed them to rule out any soil contamination which could have affected the residues over the past two millennia and “only focus on archaeologically significant compounds.” They then compared the remaining compounds with residues left from modern-day beer samples and found they matched.
Beer was important to the Mesopotamians because the malting process helps to preserve the grains for longer, while fermentation increased the grains’ nutritional value, Smithsonian noted. Without refrigeration, however, it wouldn’t have lasted very long.
Said Glatz: “Mesopotamians would have been brewing beer constantly.”
