It has been a fun set of weeks in the lab. Two weeks ago I discovered ants from our lab had made their way to the space station. Last week, we started to go through insect samples from chimpanzee nests (They are amazing! More on this soon.). Then this week, I tasted our beer.
The beer in question – one that we helped make – is delicious. It is also the result of a kind of symphony of science, a collaboration with Anne Madden (who will join us soon as a new postdoc), Anne’s undergraduate students, John Sheppard (a beer scientist), wasps, and two yeast species.
We will write more about this beer, which you will be able to drink at the World Beer Festival in Raleigh this spring, but in the meantime it has inspired me to update a miniseries I wrote for Scientific American on the history of beer, yeast and civilization.
Yeast is the unsung hero of beer; it may also be the unsung hero more generally of our modern existence.
There is a little magic embodied in every bit of bread or cheese and every sip of beer and wine. That magic is microbial and, at least in the case of the bread, beer and wine, the microbe doing the magic is yeast, of a single species, Saccharomyces cerevisiae, what one might reasonably call civilization’s yeast.
We don’t think about yeast. We buy it in packets at the store. We add water and wait. It is a creature akin to the sea monkeys you can order in the back of magazines, a sort of cheap novelty. Yet, yeast has long been, if not the bread and butter, at least the bread, beer and wine of agricultural peoples (which is to say, nearly all of us). Yeast, in many ways, saved lives (though it also takes them) and may even have been part of the reason we began to farm in the first place.
In 2012, in a series of six articles published at Scientific American, I considered the story of yeast. I am bringing these stories together here so that they can be read in one (digressive) sitting.
In chapter one, I consider the possibility that alcohol (and within it, yeast) may have been one of the reason crops were first planted, in part because in times of contagious disease and polluted water supplies alcohol might have helped keep us healthy. In chapter two, I consider new research on fruit flies suggesting fruit flies do use alcohol as medicine, just as our ancestors might have. In chapter three, I found that unknown to those studying the fruit flies, it turns out a separate literature has considered whether alcohol kills human pathogens and, in turn, influences our fate, whether historically or even today. In chapter four I consider the wicked side of fungi such as yeast. In thinking about the story of alcohol and yeast, we tend to think about having tamed yeast in order to meet our needs. But in other stories in nature, for example that of termite balls, animal societies seem to have been the ones who have been duped. Fungi, like humans, can have ill intent.
In chapter five, I write about the other societies we tend to think of as farming, all of which we tend to say “farm fungi.” But in each of these cases, including our own, it is just as reasonable to say the fungus is farming the animals. In chapter six, I conclude by considering what remains to be understood in the story of fungi, alcohol and humans. In the end, if we are to carve the story of our interactions on the cave wall, the fungi need to be there. They are among our most important partners. They may even be in control.
These articles form part of the bigger epic I’ve lost myself in over the last year or so, a story of our interactions with other species. These interactions not only influence us, they make us who we are. Yeast has shaped humans and societies, just as worms, bacteria, lions and many other species have too. Sister Sledge said it best when she sang, “We are family, all my microbes, worms, predators and me.” Well, she did not sing it just like that, but she should have.
In working hard on a story like this one, a story that has required hundreds of hours of work, lost sleep and dreams filled with writhing worms and dividing cells, one begins to wonder what the end is (or when it ends…). I can’t precisely explain why I find these species so fascinating or why I feel I need to write about them. I can’t help myself. But I think there is precedent to my wanderings.
Here, I’ll turn to the caves I was able to visit in 2012, deep caves in which, more than ten thousand years ago, our ancestors made art. A hundred years of research has concluded resolutely that it is unclear why the early peoples of Europe and elsewhere painted caves, carved bison or made small sculptures of voluptuous women. This art was not easy. The artists crawled into caves as deep as they could and painted or shaped what was meaningful in one way or another to them. They did so using fire for light. They did so when they could have been running around playing pin-the-spearhead on the mammoth. Why? Maybe it was magic. Maybe it was religion. Maybe they did not know why they were doing it either. They painted similar subjects again and again, in different forms and from different directions. They painted them because for whatever reason they “needed to.” I can’t explain why they painted the caves and yet I get it. The species with which we coexist make us human. They are who we are and so maybe that is what the cave artists were after, images of who they were, a kind of self-portrait, a confrontation in those dark corridors with their existence. They were bisons, mammoths, reindeer, lions, and magic. We are those same things and also, bacteria, yeast, wheat and worms and thousands of other species, species I want to record, if not on the cave wall, at least on paper, so we will know who they, and we, are.
Header photo: An animal scene from the caves in Lascaux in the Dordogne Valley of France as redrawn in Lascaux inconnu, Leroi-Gourhan Arl. and Allain J.