Pot Residues Reveal Secrets of Ancient Cuisine
A team of archaeologists from the University of California, Berkeley, have published a new research paper in the journal Scientific Reports, which presents evidence that unglazed ancient ceramics sometimes retain microscopic food residues which, after chemical analysis, can reveal not only what had last been cooked in a pot, but also what was cooked over a pot’s lifetime.
The co-lead author, Melanie Miller, a researcher at Berkeley’s Archaeological Research Facility and a postdoctoral scholar at the University of Otago in New Zealand, explains that the new data enables better reconstructions of the specific ingredients that people consumed in the past, which “sheds light on social, political and environmental relationships within ancient communities.”
The study finds that ceramic cooking pots record history of ancient food practices. (Archaeological Research Facility / UC Berkeley)
Chefs and Scientists Unite to Study Ancient Recipes
Over the course of a year Miller joined forces with Berkeley archaeologist Christine Hastorf, to observe a team of seven chefs preparing fifty meals with different combinations of venison, corn and wheat flour. The meals were all cooked in original black clay La Chamba ceramic pots from pre-Columbian South America. According to the paper, in addition to cooking with “donated deer road kill,” they used large quantities of whole grains which they milled and developed into six ancient recipes. Unfortunately, “the mushy meals were bland,” explains Miller, and so the researchers didn’t eat them.
The chemical residues of the meals cooked in each pot were analyzed to ascertain whether the samples found on ancient cooking vessels reflected only the last foods cooked within any given pot, or also from previous meals. Hastorf, a Berkeley professor of anthropology and food archaeology, says these particular foods were chosen not only because they were available across the ancient world, but specifically to assist the scientists in identifying their chemicals traces within the pots. The researchers monitored how the pots reacted to the isotopic and chemical values of the different food combinations.
Samples of pottery being taken from ancient ceramics. (University of Bristol)
Lipid Residue Hold the Key to Past Meals
At Berkeley’s Center for Stable Isotope Biogeochemisty the pots were tested in different cooking environments and every eighth test meal was charred in order to recreate the types of carbonized residues that are so often sampled by archaeologists inside ancient pots. Adding to the real-life variables present at ancient hunters campsites, the pots were cleaned with water and branches from an apple tree. The researchers noted that they were “surprised” that none of these ancient scrubbing tools broke during their experimentation.
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An analysis of the fatty lipids that were absorbed into the clay cookware was performed at the University of Bristol in England. This showed that “different meal time scales were represented in different residues.” For example: charred food samples taken from the bottom of pots was loaded with particles from the last meal cooked in the pot, while in the upper-patina, and in the lipid residue that was absorbed into the pottery itself, the remnants of prior meals were also discovered. The paper argues that this new method of observation not only reveals hitherto inaccessible data pertaining to ancient diets, but it also provides information relating “to food production, supply and distribution chains of past eras.”
La Chamba unglazed ceramic pots which were used in a yearlong cooking experiment analyzing chemical residues from meals. Source: Melanie Miller / Nature
Berkley and Bristol: The New Heavyweights of Ancient Food Science
The reason the pottery samples were sent from California to England is because it was a team of scientists from the University of Bristol that, back in April, announced a breakthrough in food detection on ancient pottery. At the time, I described this as “the Holy Grail of dating techniques” in an Ancient Origins news article. According to the paper which was published in the journal Nature, the new archaeological dating technique was applied to shards of pottery uncovered from a dig in East London ’s Shoreditch which contained traces of meat and dairy products, made and consumed by descendants of Europe's first farmers around 3,600 BC.
This groundbreaking new dating technique, known as Accelerator Mass Spectrometry Analysis, analyzes samples of fatty acids, rather than than traditional radiocarbon testing methods which only examine the radiocarbon found in all organic matter. The effectivity of this system was tested and approved when it correctly dated pottery samples from archaeological sites of known ages. When married with the new observation methods coming out of California, there is no question that the transatlantic collaboration, between the University of Bristol in the United Kingdom and the University of California in Berkeley, is leading the charge when it comes to exploring our ancestor’s ancient diets and the methods used to prepare and cook them.
Top image: Ancient person eating. Credit: Gorodenkoff / Adobe Stock
By Ashley Cowie