The Puratos Sourdough Library Holds Some Of The World's Oldest Starters

Sourdough has been having a moment. It began during the pandemic when amateur bakers — bored and confined to their homes with too much time on their hands — began experimenting with the time-consuming bread-making technique. Judging by the profusion of videos posted to social media during — and after —the lockdown, it would be easy to assume sourdough is some kind of new and trendy bread, but that would be oh so wrong. The truth is, sourdough has been around for millennia. In fact, it was the go-to method for baking leavened bread right up until the introduction of commercial yeast in the mid-19th century. In some ways, tracing the history of sourdough is a bit like studying the development of civilization. Perhaps that's why there's an entire library dedicated to the evolution of sourdough.

Located in St. Vith, Belgium, about 100 miles southeast of Brussels, the Puratos Sourdough Library is a repository for some of the world's oldest-known sourdough starters. The catch is that no one knows for sure how old they are. "They do not come with a birth certificate," Karl De Smedt, curator at Puratos Sourdough Library, told BBC in 2022 while mentioning some of the highlights of the library's collection, including a starter that dates to 1896 and the Klondike Gold Rush and another that's been passed through six generations of a Swiss family. So what, you may ask? Plenty of families pass heirlooms from one generation to the next. Trust us, sourdough is different.

Sourdough isn't an heirloom in the traditional sense. It's not a blanket or a Bible. It's a living organism that needs to be fed and nurtured. If neglected, it will die. For perspective, the aforementioned Swiss starter has passed through six generations. That means someone has been tending and feeding it for about 180 years. If that's not reason enough to curate a collection of long-lived sourdough starters, consider the nostalgic value of baking a loaf of bread using a starter your three-times-great grandmother made in the mid-19th century — and knowing there's a sample of said starter tucked away in a protected library collection.

That's the case with many sourdough starters curated at Puratos Sourdough Library. More than 100 bakers from around the world have contributed to the collection, secure in the knowledge that curators will carefully preserve them for future generations. One of the oldest U.S. starters on the roster, Alaskan Kaihanu D.P. is a 106-year-old specimen that dates to the Alaskan Gold Rush of the 1890s to less-than-1-year-old Millie, described in the database as temperamental.

A few things to note: The Puratos Sourdough Library is not currently open to visitors, but if you're in the area it doesn't hurt to inquire about a private tour. Karl De Smedt (AKA the sourdough librarian) has been known to welcome sourdough enthusiasts to explore the collection. If visiting in person isn't an option, the virtual library is a gateway to interesting information and surprising trivia.