Two key factors drive the movement: increased supply of local specialty grains to support local and regional mills, and new mills at the retail and wholesale bakery level in efforts to complement — but not replace — existing flour supplies.

“Sourdough is deeply embedded in human history. For tens of thousands of years, we have been basing our culture on microbial ecology,” says Erin McKenney, Ph.D., a postdoctoral researcher at North Carolina State University.