Frequently Asked Questions

What is sourdough?
Sourdough is a natural leavening agent for bread. It is made from three ingredients:

  • Flour(s)

  • Water or other liquids such as juice, milk, yogurt...

  • Two types of microorganisms: lactic acid bacteria and yeast. These are either airborne and/or present in the raw materials.

Using sourdough as a leavening agent gives bread a very distinctive taste! Depending on which sourdough is used, the result can be very different. This is because the taste and flavour of sourdough depends, among other things, on the microorganisms that are present. In fact, these can vary around the world!

What is the difference between yeast-based bread and sourdough bread?
Sourdough is the most traditional way of fermenting a dough to produce bread. It has been around for the last 5000 years! It involves fermenting flour with the natural flora present in the raw material or in the surrounding air. Natural flora typically consists of lactic acid bacteria, as found in yoghurts and wild type yeasts. This mixed fermentation has a huge effect on the complexity of the bread’s flavour! The main challenge with this traditional fermentation is the very long proofing time needed; it takes up to 24 hours to leaven the dough and develop the flavour. On the other hand, baker’s yeast was invented in the late 19th century through the work of Louis Pasteur. It allowed a very high gas-producing single cell baker’s yeast. This allowed the baker to gain a lot of time. It suddenly meant that dough could be leavened in less than two hours, and always in a more uniform way. The short proofing times and high consistency led to the industrialization of bread production. However, the flavour development is way less complex compared to traditional sourdough.

Why is sourdough important?
Historically, sourdough bread is important because it can be traced back to the ancient Egyptian civilizations of around 3000 BC. It is also important because sourdough bread is actually more nutritious than the grain from which it is made. This is because sourdough helps to release the nutrients and minerals present in the bread, making them easier to digest and more accessible for the body. Most of all though, sourdough improves the taste and flavour of bread.

In what types of bread is sourdough used?
For 5000 years sourdough was used for all types of bread. But when baker’s yeast appeared in the bakery some 150 years ago, bakers started to forget how to make sourdough. This was because using baker's yeast meant fermentation was quicker and more consistent. Today, sourdough is back, and people discover that it can be used in ANY type of bread! You’ll find hundreds of recipes in our Online Library.

What’s the Quest for Sourdough all about?
This quest is all about keeping the sourdough story alive for future generations. After all, sourdough has been around for thousands of years, and everyone has their own way of doing it. That’s why we’d love to hear how you got started, who taught you the recipe you’re using, and what makes your sourdough so unique. Think of this project like a starter. By gathering and sharing your stories in our online database, we aim to help the international sourdough community thrive and grow. There’s a reason they call it the Friendship Bread! Our project is twofold. On the one hand, there’s the sourdough database, an online platform where you can enter your recipe and share it with the world. That’s not all, though! We also created the very first sourdough library located in the Puratos Center for Bread Flavour, in Belgium. This is where we store actual sourdoughs from all around the world. Every year, we select a limited number of sourdough recipes from the database and add them to the library.

What is the Puratos World Heritage Sourdough Library?
In 2013 Puratos launched the Puratos Sourdough Library in Saint-Vith, Belgium. It gathers an authentic collection of sourdoughs (of different flavours) from all over the world. The initiative has provided a real heritage source for bakers and consumers around the world. The aim is to preserve the biodiversity of leaven agents and the know-how on using sourdough in bakery.