Emmanuelle Casanova

Organic Geochemistry Unit, University of Bristol and soon to be a MSCA IF fellow at APPSPE, MNHN, Paris.

Food residues in ancient ceramics

Pottery vessels appeared during the Neolithic and were used extensively to store, transport, cook and process food. During cooking, grease from the food migrates into the vessel walls and survive there through the ages, either complete or in a degraded form. These lipidic residues can be recovered and analysed at the molecular level. Based on the presence of specific molecules, called biomarkers, and their distribution, the source of food that was processed in the vessels is identifiable. Lipid residues from animal products are by far the most common residues recovered in the ceramics but it is also possible to find evidence of beeswax, plants, vegetables and even cereals.

Animal fats survive in the archaeological context in a hydrolysed from with the palmitic and stearic acids as the two major compounds. Measuring the stable carbon isotope values (δ¹³C) of these individual fatty acids allows to identify whether the fats came from non-ruminant, ruminant animals, and aquatic sources. This method is particularly interesting to highlight the exploitation of the dairy products of domesticated animals. It is, nonetheless, not species-specific and correlation of lipid data with the faunal records allows for further understanding about the source of animal fats cooked and processed in ceramics.

The example of Alsatian Neolithic

I studied the region of Alsace for my PhD project, a part of the NeoMilk project. During the Neolithic, two sub-groups of the Linearbandkeramik culture originating from two separate migration waves settled following the modern border of Lower and Upper Alsace. Faunal remains were dominated by domesticated animals (>96%) particularly cattle, then pig and caprines (sheep/goat). The number of identified specimens in an assemblage can be weighted for the meat available per animal (i.e. if a caprine is 1 unit, a pig is 3.3 units and a cow 7.3 units for Neolithic animal) for the data to be comparable to the abundance of lipid sources in the ceramics. A noticeable difference from the faunal remains in the two groups is the availability of pig meat being ~30% in Lower Alsace but ~5% in the Upper Alsace.

Ruminant meat and milk were extensively processed in pottery vessels of the Upper Alsace, while non-ruminant products were scarce. On the contrary, in the Lower-Alsace both non-ruminant and ruminant meat dominate the residues in the ceramics, while dairy products were scarce. The results support that the two contemporaneous sub-groups of the Linearbandkeramik exploiting their herds differently with a particular focus on ruminant products, including dairy in the Upper Alsace.

Direct radiocarbon dating of food residues: what can it tell us?

Radiocarbon dating is a key technique used to resolve the chronology of archaeological sites. I developed during my PhD and postdoc a method for directly dating ceramics from their preserved animal fats as a compound-specific approach. Among other applications, it permits to resolve the antiquity specific food commodities such as ruminant dairy by directly dating the commodity. I have applied this method to the dating of ruminant dairy residues in several regions of Europe and North Africa but also to the dating of equine products in Central Asia.

The method is particularly interesting at sites where evidence for the exploitation of a specific food commodity is scarce or unsupported by other archaeological and archaeozoological evidence. For instance, I applied the method to the radiocarbon dating of dairy residues from ceramics associated with hunter-gatherers of the Lesotho groups of 1st Millennium AD. The presence of dairy residues and their age compatible with the hunter-gatherer groups provided evidence of their access to domesticated animals, a parameter which was debated based on the morphological and ancient DNA analyses of the faunal assemblage.

These studies demonstrate the potential for organic residue analysis to enhance our understanding of past human-animal interactions. My new project, VARGAH, funded as part of the MSCA-IF will start in June hosted by Dr Marjan Maskhour at the AAPSPE, MNHN (Paris, France), uncovering the economy and chronology of early sendentary and mobile pastoralists in Iran.

My PhD was funded by the NeoMilk project (ERC-advanced grant awarded to Prof. Richard Evershed), subsquently followed by a post-doc funded by a ERC proof of concept project (LipDat awarded to Prof. Richard Evershed).