Sourdough Library

This sourdough library is hidden inside a baking corporation’s research center. Here, 105 sourdough starters and counting are stored and fed, in a long-term project to research and preserve bread biodiversity. 

In St. Vith, Belgium, Karl De Smedt has overseen the sourdough library since 2013. Fridges line the walls, and a tree-branch design covers the ceiling, evoking a nature scene. The starters on the shelves are leavened naturally, with living yeasts and bacteria from their home environments. When part of the starter is added to flour and water and baked, it results in a loaf of sourdough bread.

Until commercial yeasts became popular 160 years ago, most bread worldwide was made with starters. Depending on the microbes in the ingredients, the air, and even on the baker’s hands, each starter has the potential to produce a uniquely flavored loaf.

De Smedt regularly travels to add starters to the collection. There are starters from Japan, Italy, the United States, and more. Each was made by different people and with different ingredients, from juice to holy water. Every few months, the starters are fed with flour from their home bakeries so that their microbial makeups don’t change too much. Many starters have pedigrees going back decades, since regular feedings can keep bacteria colonies alive indefinitely. As for why Puratos is going to the trouble of having De Smedt collect sourdough starters, their CEO commented in 2015 that customers want artisanal tastes, and “the future is in sourdough.”

Famous bakeries have contributed starters, and others were gathered based on their histories, like recent additions that De Smedt sourced from the descendants of Yukon gold miners. Those starters were carried into harsh environments to make bread and flapjacks for hungry miners. Now, they have a cushy spot in the Sourdough Library, where they will be studied over time. Unlike your typical library, though, the starters cannot be checked out.

The Atlas Obscura Podcast is a short, daily celebration of all the world’s strange and wondrous places. Check out this episode about the Sourdough Library.