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Meeting the Sourdough Librarian to discuss the Future of Bread

9 May 2022

As consumers rediscover the nutritional benefits of bread, there's increasing demand for transparency, simplicity, and authenticity. Consequently, clean(er) label is becoming the norm, ancient cereals and sprouted grains are returning, and sourdough is changing bread beyond taste. We meet up with Karl De Smedt, who earned his famous nickname 'the Sourdough Librarian' after opening the world’s only Sourdough Library in the Puratos Center for Bread Flavor in Belgium, in 2013. At that time, the collection of unique sourdoughs totaled 43, while today there are more than 130. We discuss the future of bread and how sourdough is changing bread for good.

Why do you think today's modern bread should draw inspiration from the past?

Bread has been around for at least 250 generations; it's amongst the most traditional fermented foods ever created. For most generations, the only way to make bread was with sourdough. There were literally thousands of local varieties of sourdough and bread. A Turkish one was used to make big loaves, baked for 4 hours in a wood-fired oven. A famous one from Altamura was described, already 2000 years ago, as "the best bread to be had." Parents would lovingly pass their recipes on to their children, and travelers would spread local know-how to other regions.

You can still find many of these local traditions today. Nevertheless, we can only conclude that many traditions didn't survive the passing of time. Rediscovering these traditions and learning how to once again use sourdough as our leavening power, add sprouted grains for better nutrition and include a wider variety of cereals – that's vital to make bread even better than it is today. Still, being inspired by the past doesn't mean we should live in it. Today we understand much better how to make healthier bread, for example. The more we understand bread's heritage, the better the bread we can bake tomorrow.

The Sourdough Library is Puratos' not-for-profit initiative to preserve bread heritage. The world's only Sourdough Library now holds 136 sourdoughs (and counting) for future generations. How does it work? 

The loss of a unique sourdough is as irreversible as the loss of a plant species. If a jar of sourdough is forgotten about and not fed regularly, its culture of wild yeasts and lactic acid bacteria dies out. And although created from a mixture of water and flour, their simplicity is deceiving. Each sourdough is unique, and some sourdoughs are worth their weight in gold. We preserve over 100-year-old sourdoughs from Japan and the Klondike Goldrush in the Sourdough Library. We maintain sourdoughs that are irreplaceable, lovingly passed on for generations within a baker's family. All these sourdoughs remain the property of their respective owners. The Library is Puratos' contribution to bakers who keep sourdough traditions alive.

The Sourdough Library ensures each sourdoughs has a safe backup. If something happens to the original sourdough one day, the owners can rely on us to share their backup from the Sourdough Library. From day one, their sourdough is carefully looked after. Each sourdough sample is also thoroughly analyzed at the University of Bolzano in Italy; its cultures are identified and isolated so they can be preserved, while the recipe and working method are precisely documented. In addition, each sourdough is fed with its original flour every two months, following the original recipe. As such, we guarantee the safest backup a sourdough can have. The Sourdough Library is open to bakers, enthusiasts, and universities to visit by invitation. Unlike a closed vault, the library works as an eye-opener. Being surrounded by 136 pieces of baking heritage helps you realize the added value of sourdough, and of bread in general.

How come sourdough is returning in bread recipes, and why do consumers seem to love it so much?

Taste' sparked the return of sourdoughs. A slight acidity in a pizza crust, more robust butter notes in brioche, or a long-lasting fresh taste in packaged toast bread: sourdough gives every type of bread the unique taste it deserves. People's preferences for these flavors vary enormously by region and bread type. That's the beauty of it; local sourdough traditions meet local taste preferences. The return of sourdough brings back 'terroir' to bread. Just as in other foods like wine, cheese, and cacao, each sourdough bread tastes different depending on the baker's location. The origin of all this diversity of flavors in sourdough bread lies in the culture of sourdoughs. Made up of different wild yeasts and lactic acid bacteria, the culture gives the bread a flavor varying from fruity, fermented, mildly creamy, up to very acid notes.

The University of Bolzano has also proven that sourdough-made bread is easier on the stomach than yeast-made bread. They have found that sourdough bread has a lower ‘GI-index,’ a higher bio-availability of nutrients and minerals, and stays in the digestive tract for a shorter time. The way bread is fermented matters. It’s important to understand that today’s legislation still does not allow digestibility-related claims on sourdough-fermented bread. Despite this, however, the increasing evidence on sourdough digestibility is not going unnoticed. Together, with a small but influential number of consumers and bakers, we are searching for the perfect sourdough bread. We are on a Quest for Sourdough.

What's next?

Perhaps we will never fully unravel all the secrets of bread and sourdough, but the journey is full of new learnings that we try to use in modern baking. With the growing evidence of sourdough bread being more digestible and its healthy ‘halo’ growing, the request to replace bakers' yeast in even more recipes is increasing. Lately, we have seen a rise in searches for sourdough croissants and other laminated goods. At the Sourdough Library we continue to collect and preserve the world's most essential sourdoughs. We are on a quest to find wholegrain and rye sourdoughs or sourdough coming from a specific altitude or isolated region, like Alaska. The possibilities are endless. We have even applied to be recognized as a World Heritage site by UNESCO. Achieving that would significantly contribute to the biodiversity and protection of bakers' heritage worldwide.

Whether you're looking for information on making your first bread with sourdough or the future of sourdough loaves, we're here to help. For all your questions about local consumer preferences, trends, well-established applications, recipe support, and line possibilities, we have the answers – and sourdoughs – that you need. From artisan to industrial, we're helping bakers replace baker’s yeast in their recipes. Puratos’ latest innovation in the European market, dosed between 5 and 10%, consistently brings fermentation power in a limited time frame (4 to 6 hours), entirely replacing baker's yeast in a bread recipe and ingredient list. The future of bread lies in its past.