Rob Dunn has recently published Never Out of Season, the story of the homogenization of our global food supply and the risks that homogenization poses. He will build on the stories from this book and discuss his current research on one unusual sort of farm, the microbial farm used to produce sourdough bread.

Again and again, we have replaced diverse agricultural systems with simple ones. Again and again, this has posed predictable challenges for farmers and in many cases whole civilizations. The global agricultural system is as at risk due to threats from climate change and the spread of pests and pathogens as it has ever been. Dunn will tell the story of this homogenization and the risks it poses (along with several recent cases in which we narrowly avoided losing key sustenances crops globally). He will also consider some of the ways in which the homogenization of food threatens not only the crops themselves but also our health. He will then quickly turn to what at first may seem to be an unusual sort of farm, that comprised of sourdough starters, the communities of microorganisms used to produce sourdough bread. Sourdough bread is made by allow yeast and bacteria to colonize a mix of, typically, flour and water. Historically, all leavened bread in the world was sourdough bread.Then, in the 1900s, the industrial production of one kind of yeast led to the spread and global dominance of that yeast and the few kinds of bread it made, industrial, simple, bread, out of which much of the nutrition, all of the variety and most of the flavor had been removed. All is not lost though, around the world sourdoughs are still being made in the traditional way and recently we have embarked upon an effort to understand the diversity of organisms in these sourdoughs, where they come from (be it the grain, the water, or the bakers' hands), and what they offer to the future of bread. The story of sourdoughs is one with many lessons for the story of agriculture more generally. It also bears directly on our understanding of the relationship between the microbes of our bodies and those of our food.