To most home bakers, making sourdough is a fun hobby (or an act of desperation when supermarkets are out of yeast). To the folks at The Public Science Lab at North Carolina State University, it's a science experiment—and one that anyone can do at home with minimal materials. As NPR reports, researchers there are calling on the public to submit their sourdough sagas as part of a citizen science project.
Instead of using yeast from a packet, sourdough bread is made with wild yeast harvested from the air. You can cultivate wild yeast at home by combining water and flour, leaving the mixture in a warm spot for a while, and "feeding" it with fresh flour and water on a regular basis. This concoction is called a sourdough starter. Every home has its own unique yeast population, so no two starters are exactly alike.
While bakers have been relying on this process for millennia, scientists still have a lot of questions about the microbiology behind it. The new wild sourdough project from NC States's Public Science Lab aims to answer two of them: How is sourdough affected by the type flour it's fed, and how does the geography of where it's made factor in? "We know more about the deep sea than we do about some of the bacteria and fungi that are most important to us, partially because they can be so difficult to study," the researchers write on the project page. "The microbial communities in sourdough are comparatively easy to grow and study, so understanding sourdough can help us untangle some of the mysteries of the microbial world."
To participate, all you need is flour, water, and time. There are plenty of sourdough recipes online, but The Public Science Lab asks that you follow their instructions to ensure all starters are grown under fairly similar conditions. After feeding your starter 14 times over 10 days, it will be time to document its size and smell. If you're struggling to put the odor of your sourdough into words, the lab has a helpful aroma wheel on its website. Possible smells include tropical fruit, red wine, animal stable, and fart. And don't worry about killing your starter, or failing to bring it to life in the first place: The scientists are just as eager for data on "failed" sourdough starters as they are for more successful examples.