Pursuing its aim to preserve the biodiversity of leavening agents around the world, Puratos NV, Groot-Bijgaarden, Belgium, has nearly doubled its global collection of authentic sourdoughs.

The world heritage sourdough library is housed at Puratos’ Center for Bread Flavour located in the Ardennes region of southern Belgium. It opened in October 2013 and today maintains 87 sourdoughs collected from around the world, including 12 from the US. It is a non-profit initiative on the part of the company and intended as a means of safeguarding the rich diversity of sourdough.

Long before bakers yeast was commercialized in the nineteenth century, bakers leavened their breads through natural fermentation caused by wild yeasts and bacteria in the environment. Such microorganisms occur in unique populations around the world. More than 700 strains of wild yeast and 1,500 lactic bacteria have been recorded so far.

Puratos partners its library with Marco Gobbetti, PhD, a professor at the University of Bari in Bari, Italy, an international expert in fermentation technology and author of “Handbook on Sourdough Biotechnology.” All sourdoughs collected by Puratos are analytically characterized in Dr. Gobbetti’s laboratory as a step in their addition to the library.

Karl de Smodt, communications manager for bakery flavors and yeasts at Puratos, recently produced and narrated three new YouTube videos tracing the history and development of sourdoughs from Greece, Mexico and the US that are now part of the library.

San Francisco sourdough, Mr. de Smodt explained, originated with the Gold Rush of 1849 when French immigrants brought traditional breadmaking methods with them to California. There was something about the air and water in the Bay Area that yielded a unique style of fermentation. He interviewed Michel Suas of the San Francisco Baking Institute, Steve Sullivan of The Acme Bread Company and Tim Frainier of Semifreddi’s about this style of natural leavening.