This article is one in a miniseries of five articles that will be posted over the next five days about civilization, fungus, and alcohol. The first four articles are already determined, but just how this series finishes up will be determined by the comments and ideas of readers.

Solomon Katz is an anthropologist. He worked for years to understand humans. It is an endeavor that can inspire a certain distance, a remove from the world. This is the remove necessary to see people in the way an ant biologist might see ants, like tiny specks moving back and forth on the landscape, compelled by unnamed impulses, surrounded by culture. This perspective, along with a fondness for beer, moved Katz to offer his most radical hypothesis, one that reconfigures how we think about the story of civilization. He hypothesized humans domesticated and bred crops such as wheat and barley because they needed more and better grains to brew beer. To Katz, beer is the “food” most central to the development of modern society. With beer, we began.

The margins of science are dense with shy ideas, variations in a minor key, micro-theories about micro-stories. Katz’s is not one of them. His strikes a low, heavy, chord at the heart of one of the biggest questions we can ask about ourselves: What happened the day everything changed, the one on which we began to plant and harvest crops? With agriculture came settlements, kings, waterworks, social classes, complex buildings, politics, writing, recorded history and Ipads. All of this came with a startling inevitability. Similar trajectories unfolded independently around the world1. Nothing could be more straightforward than making a hole in which to put a seed. You push your fingers into the Earth. You take the seed, branch or root. You drop it in and cover it and pull the weeds. What has grown is unfathomably complex. It is a modern world held aloft by the leaves, or more literally the descendants of that first farmed plant. The question is why we planted it, and whether it could really have anything to do with beer.

[Image: Wild Wheat, Triticum araraticum, the seeds of which would change the face, and taste, of Western history]

You depend on agriculture. The atoms in your body come from relatively few crops. Essentially none of your atoms are derived from wild plants or animals. If you were born in the U.S., more than half of your body may be composed of atoms derived originally from corn. We tend to see agriculture as an invention for which we have failed to record the inventor, akin to the telephone or the cotton gin. Somewhere far enough back in time there is, in this telling, a Henry Ford of the wheat seed. But maybe it makes more sense to assume agriculture would and could be invented, but to ask, once it was be it is more like a decision, a possibility that was always present but that eventually we chose to embrace. After all, agriculture arose again and again. But why would we choose agriculture? Agriculture led to progress, but also sorrow. Lifespans shortened and a range of health metrics, such as height, bone density and pathology, worsened. Class structures developed. The poor and rich came into existence. Why would any society choose the path to a harder life? In the fertile crescent, Katz thinks the answer is beer.

The first beers would have been accidental. A mash of wheat and sprouted barley was left out, in a clay pot, on a clay shelf, in among the mud. Perhaps yeast fell in and fermentation began. Yeast is everywhere. Someone drank the result (we all known someone who would) and, in one way or another, found it worth making more of, using whatever yeast fell down out of the sky, like luck. Beer yeasts are single-celled fungi. They eat simple sugars. As they do, they produce more complex compounds, the nuance or lack thereof connoisseurs favor, and alcohol. The first sample would not have been high in alcohol content. But, if someone drank enough, they would have started to feel the party coming on2.

[Image: Yeast cells of the species Saccharomyces cerevisiae, perhaps the first domesticated organism. Perhaps not]

Beer and bad decisions are no strangers. You have your examples. I have mine. It is said that the city of Raleigh, where I live, was founded when a local landholder, over too many beers, convinced government officials to buy his land to build a city. The land, it would later become clear, was no good for farming, far from rivers and oceans and otherwise a humble place to begin (out of which a lovely city has nonetheless grown). The first bad decision beer led to though might have been agriculture.

By the time agriculture became a possibility, people would have been living in densities greater than any experienced before by a primate. They were densities sufficient to cause social problems-a kind of proto-urban pathological strife. Maybe beer and other intoxicants might have quelled some of these problems. “Dude, I’m sorry man, I did not mean that about your mom. Have you tasted my fermented wheat? Its all cool.” Maybe it made more. Or maybe, with the onset of social discontent the demand for substances like beer simply increased. Beer though also had other things to offer. Thanks to yeast, beer has more of several key nutrients, such as the B vitamins, than do the seeds out of which it is made. Beer also allowed food to be stored, as beer. And then there is disease… Dense humans favored new diseases. Epidemiologists refer to the emergence of diseases associated with settlement as the first epidemiological transition. Beer might have solved this too. As Katz put it, "beer drinkers would have had a ‘selective advantage’ in the form of improved health for themselves and ultimately for their offspring.” But even as beer might have saved us, it asked something in return. It was a deal. To make enough beer to satisfy early demand we had to begin to farm.

Katz is not the first to imagine the domestication of wheat and barley was for beer first and food second, but he has been the most eager and comprehensive in his arguments3. What Katz envisioned was, as he put it in an interview with the New York Times several years ago is that “the initial discovery of a stable way to produce alcohol provided enormous motivation for continuing to go out and collect these seeds and try to get them to do better.”

[Image: Sumerian beer drinkers (top row).]

That beer has nutritional value absent from wheat and barley is indisputable, as is the observation that beer makes us feel good (at least initially). But, let’s return though to the issue of disease. Katz did not dwell on disease, but disease definitely dwelled in the early settlements where be began. Agriculture followed the first settled human villages. Such gatherings of family and friends are nice, but they are just as often contagious. High densities of people lead to more opportunities for diseases to pass body to body. The greatest challenge in being a parasite, whether a worm, bacteria or virus is getting from one host to another. When hosts are rare and far apart, a parasite has trouble finding them. Imagine having to find a single rare species out in the Amazon or the Serengeti. But now imagine you must do so, as is the case for many parasites, without being able to walk. You depend instead on riding the wind, the water or the hairy body of a mosquito. If you are a parasite that lives by such chance, most of your children will die and so you make many children and favor common hosts, like settled humans.

As humans began to build permanent homes and stopped migrated seasonally, the relatives came to town and everyone, gathered together. Suddenly, the odds a good wind, a river’s flow or a mosquito’s flight, would take you from one human to another increased, dramatically. As those odds increased, not only did many parasites and pathogens evolve the ability to “use” humans, many switched to using us exclusively.

Nearly all water borne diseases of humans evolved after humans settled and share a basic feature of their life cycle. They enter the water when we poop and reenter humans as they contact that feces directly or drink infected water. Human settlements emerged before good waste disposal systems were developed. The edge of town would have buzzed with flies and pathogenic opportunity. Perhaps it was in this context that the need for agriculture arose, at least in the fertile crescent, at least maybe. It arose as a way of coping with human interactions and human diseases. Beer made you feel good, beer had nutritional value AND beer might kill pathogens and so drinking beer and other fermented beverages would save lives from diseases like typhoid and cholera by preventing them from being passed from one person to the next. Beer was the last wall of defense between life and death.

The first alcoholic beverages would not have had a high alcohol content. High alcohol content drinks depend on a good supply of oxygen and alcohol tolerant yeasts that appear to have evolved only after many generations of beer and eventually wine brewing. The first beer was light on both buzz and taste. You might add some honey or dates. It would then taste better, but not good, not compared with foods that could be gathered, foods like figs, berries and wild meat4. The first beers were not the garden’s delicious fruits but instead its somewhat bitter, but fun, medicine.

[Image 4: The birth of civilization?]

Maybe, because of all of these benefits, albeit some of them very short term, we had to begin to farm, to feed the yeast that made our beer. Katz offered this hypothesis, but then he could not think of a test. Well, of course, he could look at the archaeological evidence, which he did. If he were right, he would have expected to see that the evidence for making beer predates that of, for example, making bread. It seems to. He would also expect to see some settlements that occur before agriculture. There do seem to be some. Then what?

Few papers have been published on Katz's idea in recent years. It lay fallow, at once interesting and untended. Science can be beautiful, powerful and elegant. It can also be frustrating. Ideas can wait generations to find their moment. Sometimes good, right, true and elegant ideas never find their time. They sit like seeds, waiting for light that might not come. Katz’s idea seemed as though it might become one of those ideas. Then, just this year a group, led by Todd Schlenke at Emory University, working on, of all things, fruit flies, made a major discovery. Schlenke and his students did not know about the work of Katz, but what they did know was how to test whether animals drink booze to kill their pathogens. They do.

Read on...

Table of evolutionary contents: Here you can skip ahead or backward to the other chapters in the story of the other species in our daily lives, whether they be the cow, the chicken, the hamster, bacteria (on Lady Gaga, on feet, in bathrooms, as influenced by antimicrobial wipes, as probiotics, in the appendix), pigeons and urban gardens, house sparrows (to be published next week, stay tuned), predators, diseases, dust mites, basement dwellers, lice, field mice, viruses, yeast, the fungus that produces penicillin, bedbugs, houseflies, or something more.

Or for the big picture of how Rob thinks these stories come together to make us who and who we are, check out The Wild Life of Our Bodies. Rob Dunn is a writer and evolutionary biologist in the Department of Biology at North Carolina State University. Find him on twitter at robrdunn. Find him in person somewhere in Europe with his family while they are all on sabbatical.