An Interview with Archaeologist and Fermentation Fan, Dr. John Speth

In the never-ending pursuit to harness the secrets of ancient foodways, Zingerman’s Bakehouse presents Dr. John Speth, Emeritus Professor of Anthropology at the University of Michigan, to share, over a light meal, the fascinating role that fermented foods played in the successful colonization of the northern hemisphere at the upcoming event, The Power of Culture in Shaping Human Foodways, Thursday, October 10th, 6-8 pm ($45/person). Sign up here.

In anticipation of this BAKE! Special Event, I asked Dr. Speth to share a bit of his perspective on fermentation and a hint of what we can expect during his talk.

kimchi aging

Did you always love fermented foods? 

Aside from cheese and yogurt (and a beer now and then), fermented foods have never played much of a role in my diet or eating habits. My interest in fermented foods actually came about because of my career as an archaeologist. I have been interested in the evolution of the human diet and foodways, with a focus on the major changes over the last 2 million years in the way our ancestors prepared their foods.



– The control of fire and the beginnings of cooking occurred about 2 million years ago.

– The introduction of boiling technology began sometime between 250,000 and 40,000 years ago,
long before the invention of pottery, and had an impact on making starches more digestible.

– The origins of seed grinding to make flour came about 25,000 years ago,
long before cereals like wheat were domesticated.

– The first earth ovens and pit-baking happened about 10,000 years ago. 


I am also very interested in how these changes in food-processing technologies have impacted human health, both positively and negatively (e.g., the nature of our gut flora; our susceptibility to autoimmune and cardiovascular diseases; our access to omega-3 fatty acids and our ability to biosynthesize to DHA; changing rates of tooth decay; etc.). 

So why fermentation, in particular?

The development of fermentation is one of these technological introductions, with many interesting consequences. For one thing, most scholars seem to think that it originated with the making of bread and beer some 8,000 years ago or so. I suspect humans were deliberately fermenting foods at least 100,000 years ago and probably as much as 300,000 years ago. 

Fermentation, like cooking, provides a way of softening and “pre-digesting” foods before you even put them in your mouth. This means we can extract more calories and nutrients from food at greatly reduced metabolic cost (i.e., digestion is both faster and more efficient). 

The successful colonization by humans of the northern latitudes of both the Old and New Worlds may not have been possible without fermentation. As one moves farther north, edible plant foods become less and less available, and humans have to rely increasingly on meat to survive (think of traditional Eskimos or Inuit, whose diet was nearly 100% meat). But muscle meat has very little vitamin C to start with and cooking destroys much of what little there is. Scurvy, therefore, poses a major threat to life in these northerly habitats. Fermentation provided a way to preserve the precious vitamin C content of meat and allowed humans to expand into such environments without fear of scurvy. Even foods like Kimchi may originally have been developed as a way of preserving vitamin C to help stave off scurvy in environments with long cold winters.

pirate with a treasure box
Arrgh, scurvy. Did the pirates understand the value of fermentation?

Capt. James Cook, during his voyages of exploration in the Pacific in the late 1700s, carried large quantities of sauerkraut on board his ships, which he made his sailors eat. Most didn’t like it, but Cook got them to eat it by allowing the sailors now and then to eat with the officers if they agreed to eat sauerkraut as part of their rations!


Which foods do you think are the most misunderstood? 

Overall, we have a poor understanding of the many potentially negative nutritional consequences of relying on foods made from domesticated plants and animals (livestock that have been grain-fed or grain-fattened). I would also add that we don’t yet fully grasp the negative impact of foods that have been produced under industrial conditions (e.g., mechanically extruded or acellular starches; the heavy use of salt, preservatives, and colorings in processed foods; excessive use of high fructose corn syrup, sugar, and other sweeteners). Many of these processes and additives were introduced on a large scale after WWII, and their negative health impacts are very much with us today.

In the course of your research, are there foods, drinks, or food preparation methods that you’ve come across that you would never eat? 

As an anthropologist, when I’ve been in the field, I’ve eaten almost anything. This was often necessitated by the fact that one’s hosts will offer you foods, often special ones because you are their guest, and it would be extremely impolite to refuse (this has included sheep brains, testicles, eyeballs, and innards of all sorts; bread covered with a spread made of a local clay; “agua miel,” the slowly fermenting sap (en route to becoming pulque) of the maguey plant, complete with dead flies afloat in the middle, etc. I have never been in a context where insects were a main course, so it would take some “doing” to coax them down (but I would if I perceived it was important to the hosts). When I’m back in Ann Arbor, my diet is far less eclectic!

A common example of fermentation is the change of cider into vinegar. Apple Cider Vinegar has long been touted as a cure-all. Any thoughts on the beloved ACV?

People are always searching for magic elixirs and 3 bottles of vinegarcures. Personally, I don’t believe they exist. I’m sure ACV under some circumstances, for certain people, and used in certain—probably moderate—amounts, may be helpful. But we each have our own unique genetic make-up, and hence we may each have our own unique way of responding to what we put in our mouth, including ACV. Thus, as a blanket prescription, I would be wary. I suspect in the long run, it would be far more healthful for those of us who can to exercise; stay away from industrialized “junk” foods; to the extent that we have any control in the matter, reduce the quantity of chemicals to which we are exposed, both at home and outside the home; and most importantly learn to “get along” with bacteria rather than trying to do everything in our power to kill them. (It is estimated that we each have within us something like 100 trillion bacteria. They are us. We’d better learn to live with them!)

What will your research focus on next? 

I have a number of research interests that are still “brewing.” One of them concerns the origin of boiling. We know surprisingly little about it, and yet boiling has had a tremendous impact on our diet and foodways, especially with regard to making starchy foods digestible. Look at any cookbook and you’ll quickly see how many recipes involve heated water at some point in their preparation. We know that humans were boiling at least 35,000 years ago, long before the invention of pottery, but how much further back in time it goes, and how it impacted our diet and health, remain largely unexplored. The same is true of fermentation. Most scholarly writing on the subject seems to stop with the invention of bread and beer, a mere 8,000 to 10,000 years ago. I suspect it goes back to Neanderthals and maybe even further (probably as much as 300,000 years ago). 

I am interested in exploring fermentation’s role in human evolution further, both to find ways to determine its antiquity, and to figure out how humans did it while avoiding dangerous pathogens like botulism. For both of these research endeavors, I need to work cooperatively with biochemists and microbiologists.

Join us to learn more from Dr. Speth at the upcoming Bakehouse talk, The Power of Culture in Shaping Human Foodways, Thursday, October 10th, 6-8 pm ($45/person). You’ll enjoy a light meal, including an assortment of naturally leavened Bakehouse breads and Creamery cheese, sausage, sauerkraut, and Hiday grass-fed vanilla yogurt with Nemeth Farms Apple Compote. Sign up at 

By Jenn Hayman, Director of Marketing, Zingerman’s Service Network

Illustrations originally created for our fellow Zingerman’s businesses, Miss Kim and Mail Order

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