Ancient Cocoa Traces Found at Chaco Canyon, NM

Theobromine, the key component of cocoa that gives us that little boost when we eat our favorite chocolate, also stays around a while. A long while, to be exact. So when ancient peoples didn’t wash their dishes well, some traces  of theobromine stayed behind and, thousands of years later, we can detect those traces and link them to specific dates. Well, at least specific date ranges.

Last July, I wrote about the oldest trace of cocoa found in Soconusco, now Chiapas, Mexico. That find was important because it dated cocoa consumption to some time in 1900 BCE. But the location as such was no surprise because Soconusco was a know cultivation area of cocoa throughout the times of the Olmec, Maya and Aztecs.

Now we have a new discovery of cocoa traces and this time the location is as unexpected as the time frame. Using pottery shards from a number of vessels found at the Pueblo Bonito site in Chaco Canyon, New Mexico, Archaeologists Patricia Crown of the University of New Mexico and Jeffrey Hurst, Principal Scientists at the Hershey Company, have established that cocoa was consumed at Pueblo Bonito about 1,000 years ago.

The genesis of this discovery is interesting in itself. After all, why would anyone suspect that the Chacoans consumed cocoa given how far away the lived from the areas where cocoa could grow.

Prof. Crown is an expert on ceramic vessels in the U.S. Southwest. So she knew about the cylindrical vessels found at the Pueblo Bonito site. Her first inkling came in a conversation with a colleague who pointed out that  Mayan cylindrical vessels were used to consume cocoa drinks. The next step was simple curiosity:  “I wondered if possibly the Chacoan ones might have been used in the same way, since the forms are similar,” she told me in a short email interview.

The same colleague introduced her to Jeffrey Hurst who, having lived in New Mexico, “was intrigued by the idea.” They selected sherds from five vessels and, since there was no visible residue, ground off some of the interior surface, treated that residue and analyzed it using high pressure liquid chromatography (HPLC). Three of the samples derived from cylindrical jars turned out to have cocoa residue on them.

Given the distance the cocoa had to travel (see the map), we can safely assume that cocoa was not an everyday drink and reserved for special occasions. Prof. Crown assumes that the Chacoans, like the Maya, consumed cocoa drinks for ritual purposes to mark important events (birth, marriage, death) and/or dates (solstices, etc.).

What’s truly amazing to me is the length of the supply chain necessary to get cocoa beans to Chaco Canyon. That required a far more elaborate trading system than I  ever imagined (not that I have special knowledge about this). It should not have come as a surprise, though. After all, the Mayan kingdoms has established elaborate trading networks involving both porters and ocean trade.

But somehow, I had not even thought about that trade reaching so far north. I must have fallen victim to the modern map with its images of borders that, of course, are far more recent.

But trade is a two-way street. What might the Chacoans have exchanged for their precious cocoa? That’s not entirely clear, but Prof. Crown pointed out that the Chacoans are know to have processed turquoise for exchange and it’s quite likely that these stones were exchanged for cocoa.

That makes sense to me given how priced precious stones were among the Maya and, later, the Aztecs.

So there you have it. The U.S. has a chocolate history that goes back 1000 years.