Continuing with the plethora of Scottish prehistory news this month – especially regarding crannogs and cereal cultivation and consumption – we’re exploring recent research that has analysed organic residues found in pottery from four Neolithic Hebridean crannogs.
The recent discovery and excavation of Neolithic material at crannogs in Loch Langabhat, Loch Bhorgastail (ABOVE), Loch Arnish, and Loch An Duna (all dated to the 4th millennium BC) presented an opportunity to analyse the pottery from these sites for absorbed residue left over from their use. It was hoped that the residue would have remained preserved in the anoxic conditions of the watery environments from which they were recovered. As described by the multidisciplinary team of researchers who conducted the study (the results of which were recently published in Nature Communications: https://doi.org/10.1038/s41467-022-32286-0): ‘The fundamental principle of the analytical approach used in this study, commonly referred to as organic residue analysis (ORA), is that lipids liberated from food cooked or stored in pottery vessels during use, can migrate into the ceramic matrix of unglazed pottery vessels and subsequently can be preserved there.’
In analysing 59 pottery sherds from these four sites, the team used a new technique that allowed them to identify cereal lipid biomarkers, namely alkylresorcinols, in 16 samples. While detecting specific cereal species can be difficult given the changes that can happen either during cooking or following burial, they were able to determine a dominance of the alkylresorcinal AR-21, which is characteristic of wheat, and a total absence of AR-25, which is dominant in barley. This was somewhat unexpected as in many other Neolithic sites across Scotland barley appears to have been the dominant grain. This does not mean that barley was not consumed at these crannogs, however, just that it was probably not cooked or stored in the pottery recovered.
The data also showed that, in eight of the 16 samples with evidence of cereals, there were signs of them having once contained dairy fat as well – but only one pottery sherd, found at Loch Bhorgastail, showed evidence of both cereal and carcass fats. This suggests that wheat and dairy appear to have either been frequently cooked together in some sort of gruel, or otherwise stored in the same pots (not necessarily at the same time). In contrast, meat and cereal do not appear to have been used together very often. There also appeared to be a possible connection between the shape of the vessel and their contents: smaller rimmed jars were more likely to have been used for dairy products and cereals, while larger rimmed ones seem to have been reserved for meat.
TEXT: K Krakowka