Most archaeological excavations do not find golden statues or treasure troves, like what is portrayed in films, but rather ceramic shards. To the general public, this might not seem like an important find but these fragments offer a lot of information. Organic residues found on or in ceramic matrices or plasters (see Figure 1) are one feature, in particular, that contain valuable archaeological data. These residues represent precious history and the analysis of such residues can recover many aspects of ancient ways of life including diet, cooking, food storage, etc. (Pecci 2014).

Figure 1. Analyzed pottery fragment with an attached food residue. https://doi.org/10.1016/j.jas.2016.07.004.

So what exactly is organic residue analysis? It is a method that utilizes “analytical organic chemical techniques to identify the nature and origins of organic remains that cannot be characterized by using traditional techniques of archaeological investigation” (Evershed 2008). There are two main approaches used when performing residue analyses. The first is the analysis of lipids through identification of fatty acids by gas chromatography-mass spectrometry (GC-MS), often coupled with the analysis of carbon stable isotopes (Pavelka 2016). The second is identifying source-specific proteins by either mass spectrometry or by more traditional immunological methods and using peptide mapping (Pavelka 2016). Both approaches have their advantages which should be taken into account. Lipids are less susceptible to “leaching” and “diagenetic degradation” than proteins but peptide mapping for proteins is very analogous and can detect distinct differences in amino acids for individual species (Pavelka 2016).

Many studies have been done on recovered ceramics using organic residue analysis to further study the diets of past societies and also show connections between them. A study conducted by Boyd et al. (2006), focused on the consumption of maize in North America through the analysis of food residue for starch and phytolith content. Their results showed that maize consumption was more widespread than believed. They examined small-scale societies living at the northern edge of the Great Plains (see Figure 2), where the role of domesticated plants in their diets was hidden due to little to no archaeological evidence using traditional methods. However, residue analysis from ceramic pieces in this area demonstrated that maize was evidently present and even became an important dietary. This then raised questions as to whether the maize presence was reflecting local production, trade, or both. Boyd et al. observed that one sample obtained from a large loop-handled pot, which was the only one recovered at that site, was similar to another location’s traditional style pot where maize was known to be grown locally; so it is reasonable to suspect that it was acquired through trade.

Figure 2. Location of study sites, and Middle Missouri region within the Great Plains (shaded in gray). https://doi.org/10.1016/j.jas.2008.04.008.

As the organic residue field further expands and develops, it can propose evidence to challenge many long-standing archaeological hypotheses (Evershed 2008). A critical step forward will be treating recovered ceramics as biological material that is susceptible to irreparable damage and contamination so that no potential information is lost (Pavelka 2016).

Further Readings

https://doi.org/10.1016/j.quaint.2016.04.015

https://www.science.org/doi/full/10.1126/sciadv.abb9314

References

Boyd, M.,  T. Varney, C. Surette, and J. Surette. 2008. “Reassessing the Northern Limit of Maize Consumption in North America: Stable Isotope, Plant Microfossil, and Trace Element Content of Carbonized Food Residue.” Journal of Archaeological Science, 35: 2545-2556. https://doi.org/10.1016/j.jas.2008.04.008.

Evershed, Richard P. 2008. “Organic Residue Analysis in Archaeology: The Archaeological Biomarker Revolution*.” Archaeometry, 50: 895-924. https://doi.org/10.1111/j.1475-4754.2008.00446.x.  

Pavelka, Jaroslav, Ladislav Smejda, Radovan Hynek, and Stepanka Hrdlickova Kuckova. 2016. “Immunological Detection of Denatured Proteins as a Method for Rapid Identification of Food Residues on Archaeological Pottery.” Journal of Archaeological Science, 73: 25-35. https://doi.org/10.1016/j.jas.2016.07.004. 

Pecci, A. 2014. “Organic Residue Analysis in Archaeology.” In: Smith, C. (eds) Encyclopedia of Global Archaeology. Springer, New York, NY. https://doi.org/10.1007/978-1-4419-0465-2_334.