The Belgian Sourdough Experiment
While our Global Sourdough Project will tell us which factors tend to predict what is in your sourdough, perhaps even suggest where you might need to travel or what you might choose to add to your starter if you want to foster a particular species, it is not an experiment.
In an experiment, one manipulates one or more variables of interest and controls for the other variables. In the context of sourdough starters, we could manipulate many variables, but one in particular fascinates us, the potential that the person who makes the sourdough starter imparts some of his or her flavor to the starter. The Lactobacillus bacteria, for instance, that play a key role in starters, include species known from human bodies. Lactobacillus bacteria inhabit vaginas, guts, and even, sometimes, armpits and belly buttons. It is entirely possible that when you make a starter that the particular Lactobacillus that you seed it with are your own symbionts. But how would we possibly know?
This is where the experiment comes in. In the Summer of 2017 we united bakers from around the world at Puratos in Belgium. In the days leading up to the experiment, each baker began a starter at home to bring with them. Once in Belgium, we sampled the microbes on the baker’s hands and in their starters in order to know which microbes were present. Of course, we also baked and sampled bread made with each of the starters so that we could determine how important the person who made the starter, and their microbes, were not only to which microbes were in the starter but also the chemistry and flavor of the bread.