Fantastic yeasts and where to find them: The science behind sourdough starters On Location: April 2, 2021 Replay Video Sourdough bread has nurtured humans for thousands of years -- perhaps even more so during the bread-making hype of the COVID-19 pandemic -- and bakers have perfected the craft of making it over generations. Now, scientists are beginning to understand the identities and activities of the microbes in sourdough that are key to making a delicious loaf. "People are making sourdough all over the world -- it's the most ancient form of bread-making and an ancient form of fermentation," said Elizabeth Landis, a microbiologist at Tufts University near Boston, Massachusetts. But she added, "We really didn't know a lot of the diversity of microbes that are currently in people's starters."MORE: Back to Basics: What you 'knead' to know about making bread from a master baker