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What It’s Like to Refresh the Sourdough Library: A Behind-the-Scenes Look

  • jlecot
  • 6 days ago
  • 3 min read

Updated: 4 days ago

Sourdough Story


Imagine spending a week surrounded by +150 living sourdough cultures from around the world. That’s exactly what it’s like to refresh the world’s only Sourdough Library—and it’s as magical as it sounds.


From Australia to Belgium: A Sourdough Dream Begins

Back in 2013, I was working in a remote supermarket bakery in Australia. Sourdough wasn’t yet the global trend it is today, but one article in an Australian baking magazine changed everything. It mentioned something called the Sourdough Library—a place in Belgium dedicated to preserving sourdough cultures from around the world.


I was instantly fascinated.


After completing my baking course, I set off on a three-month European adventure. I baked with master bakers in France, learned from Cornish bakers in the UK, and—yes—visited the legendary Sourdough Library in St. Vith, Belgium.


What Is the Sourdough Library?

The Sourdough Library, curated by the one and only Karl De Smedt, is home to over 150 sourdough cultures, each with its own story, origin, and flavor profile. It’s a sacred space for fermentation lovers, where sourdoughs are preserved, studied, and celebrated.


Fast forward a few years, and I now work for Puratos as a Sourdough Ambassador, traveling the world to share my passion—and learning how to care for the “sourdough babies” in the Library.


Feeding the Sourdoughs

So, how long does it take to refresh 150 sourdoughs? The answer: several days, a team of four, and a whole lot of cleaning, measuring, and mixing.

Each sourdough is stored in a sanitized glass jar and can “sleep” for up to two months. When it’s time to refresh, we follow the original baker’s recipe using the same flour they provide. Some sourdoughs require seed mixes, others use a blend of three flours—some of which we even mill ourselves.

And yes, I tasted every single one. From creamy and acidic to cereal-rich and funky, the flavor profiles were as diverse as the cultures themselves.


The Science of Refreshing

When a sourdough develops a layer of liquid on top—called the hooch—it’s just a sign that it’s hungry. Stir it in, feed it, and it comes back to life.

The refreshment process is precise. Every tool is sanitized, every measurement exact. Mixers run full steam for four days straight. It’s intense, but incredibly rewarding.


Personal Highlights from the Library

  • No° 64 – China: Sticky, wild, and full of character. A messy but memorable refresh.

  • No° 66 – Australia: From Brett Noy of Uncle Bob’s Bakeries—my mentor and the person who encouraged me to contact Puratos. Baking with his sourdough in Belgium was a full-circle moment.

  • No° 104 – USA: Will Grant’s pizza sourdough from “That’s Some Pizza,” originally created in 1897 and revived in 1983. A living piece of pizza history.

  • No° 125 – Slovenia: From my dear friend Anita Šumer, whom I met during the first Quest for Sourdough adventure. We even created a shared culture called “The Hooligans.”


🧡 Why It Matters

Refreshing the Sourdough Library isn’t just about feeding dough—it’s about preserving global bread heritage. Each culture represents a baker, a region, a tradition. And by caring for them, we ensure that future generations can experience the magic of sourdough.

“As I placed the final sourdough back into its jar, I felt a deep sense of satisfaction. These cultures are in good hands—and ready to inspire the world.”

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