From 2,800-year-old charred food lumps, a window into past civilizations

At a site in southern India, archaeologist Kathleen Morrison and colleagues discovered the remains of two types of dough, offering insights into how the region’s dietary practices have evolved.

Kathy Morrison sitting at a computer in a lab, gesturing to grad student Moriah McKenna. They both wear white lab coats. In front of them is a computer screen with what looks like a large rock. Next to the computer is a large microscope with its light on.
Archaeologist Kathleen Morrison (center) and anthropology doctoral student Moriah McKenna discuss one of the charred lumps from a 2010 excavation in southern India. The image is possible thanks to a new microscope, seen here on the right, that takes and stitches together high-resolution images in incredible detail. (Image: Eric Sucar)

Charred lumps of plant material may not sound like a window into past civilizations. But for Penn archaeologist Kathleen Morrison and colleagues Jennifer Bates from Seoul National University and Kelly Wilcox Black from the University of Chicago, several such remnants offered insight into the dietary habits of people living in southern India some 2,800 years ago. 

“These are usually considered unidentifiable,” says Morrison, the Sally and Alvin V. Shoemaker Professor and chair of the Department of Anthropology. “You typically can’t analyze them because they’re just blobs of charred material.” 

A few years ago, however, Penn had acquired a new microscope that takes high-resolution images and stitches together the images. “You can see things in amazingly sharp detail,” Morrison says. So, she and Bates, a former postdoc in Morrison’s lab, started analyzing the material under the microscope. 

In a paper published in the Journal of Archaeological Science, the researchers detail what they learned. Inside a large pit from the historical period known as the early Iron Age, they identified a dough made from millet, likely used to make a sort of flatbread, and a dough made primarily from pulses like beans and lentils. Penn Today spoke with Morrison about the findings and why they’re important.

A dark-brown lump on top of a pile of light-brown sand.
Morrison and colleagues analyzed all the charred lumps they found in the Iron Age pit, including this one, which turned out to include millets, a wide variety of hearty grains that grow well in dry areas. (Image: Courtesy Kathleen Morrison et al.)

Can you describe where you found the charred lumps?

Between 2003 and 2010, my students and colleagues and I were excavating an archaeological site in southern India. We had been working in that region for a long time, looking at the changes in environment, farming, and food practices. We’d found a site called Kadebakele decades before, and we’d always wanted to excavate it. It has this long sequence, from the beginning of agriculture all the way up into the present, so it tells us how farming, animal husbandry, and food practices have changed over the past 5,000 years. We finished excavating there in 2010.

Analysis took place over the past year or two. Archaeological work is like that. We excavate and then it takes us years to finish analyzing all the material.

Did the time between excavation and analysis harm or affect the materials?

Charred remains will last indefinitely. If you think about it, why would almost 3,000-year-old material survive in the ground for so long? Plant remains typically just decay. They don’t last that long. But if they’re burned—charred but not completely burned up—those little pieces can last 10,000 years or more, as long as they don’t get crushed.

When we find charred seeds or food lumps, it’s often from a mistake. If people are using wood or animal dung as fuel, we’ll find pieces of wood charcoal and pieces of animal dung, as well as charred remains from cooking. People don’t tend to deliberately throw their dinner into the fire. It’s the seeds or other remnants that don’t get burned up all the way but get burned enough that they’re going to last a long time.

What did the lumps turn out to be?

Some were charred animal dung, and some were food. People cooked over an open fire in those days. When they burned the food, they threw it away. Other scientists had recognized that these were lumps of food material but didn’t look much closer. With our new microscope, we realized that we could identify some of the components in them, impressions or pieces of grains, like millets, as well as record the structure of the lumps.

We analyzed all the charred lumps from the Iron Age pit but picked two to focus on in our paper. One we determined was a sort of batter or stew made primarily out of legumes. Iron Age people in southern India ate a lot of legumes, and they had a huge variety, too. We always tend to think of grains as being the staple, but in southern India it seems that legumes were as or even more important than grains at this time.

The other lump was also very exciting. It seems to be made from, among other things, millets, which are a wide variety of hearty grains that grow well in dry areas. In this area, people grew a lot of millets and pulses in the Iron Age. It wasn’t until much later that rice agriculture really became important. Comparing our food lumps with some experimental data, this one matched the features of flatbread dough. People still eat millet flatbreads in this region, suggesting a really long timeframe for this practice.

A site called Kadebakele in southern India, shown here in 2010. The research team maps the top of the pit (left) before excavating it (right). The dig led to the discovery of two different types of dough. (Image: Courtesy Kathleen Morrison et al.)

You mentioned that other scientists had already identified these remains as food. Can you discuss what your findings add to the scholarship?

Archaeologists are good at figuring out lists of ingredients. We can identify charred seeds; we can identify animal bones. We can say people are eating this kind of millet and these kinds of pulses. What we don’t usually know is how they prepare it. How do they process it? What combinations make a meal? We don’t really know. Analyzing these lumps gives a glimpse into something more than just a list of ingredients, a better sense of the combinations and preparation.

What are the implications of your analysis and findings?

We’re always curious about how people lived at a particular time and how things changed or didn’t over a long period. One reason we started working at Kadebakele in the first place is because I became very interested in the development of what you could call ‘elite cuisine,’ rice-based South Indian cuisines associated with the wealthy that are incredibly water- and labor-intensive. At the same time, there was also the food of ordinary people: millet, pulses, the same things we found in those samples. How did that social and economic differentiation emerge?

We started work at Kadebakele to get at the long history of farming and food in that region—before this, we had only looked back 600 years—and we can now see that what people ate is strikingly like the way people still eat now, particularly those who can’t afford to eat the rice-based irrigated crops.

Is the charred lump work finished?

We plan to do more analysis on the lumps, some chemical analysis, because we have unanswered questions. We can identify the bits of seeds, but were there animal products mixed in? We haven’t done this yet, but I think this method is a good way to use previously unidentifiable charred lumps to look at food practices. It tells us something very specific about the early Iron Age in south India, about daily life and what cooking might have been like. But this analysis is only from one short period of time, and we have samples from a much longer sequence waiting to be studied. In short, we have more work to do.

Kathleen Morrison is the Sally and Alvin V. Shoemaker Professor and chair of the Department of Anthropology in the School of Arts & Sciences at the University of Pennsylvania and a curator in the Asian Section of the Penn Museum.