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Sourdough Guide: Everything you need to know about sourdough

26 Sep 2023

Learn everything you need to know about sourdough in this ultimate guide to everyone's favorite fermented bread.

With insights from Puratos sourdough experts, read on to find out where sourdough originated, what its health benefits are and how to make top quality sourdough.

What is sourdough bread?

Sourdough is a natural leavening agent for bread (also known as a rising agent) that causes the expansion of dough to create a light and airy mixture. Sourdough is also an essential ingredient that adds depth of flavor to recipes of all kinds. 

While there are many recipes for sourdough starters, just three main ingredients are needed to make sourdough.

These are: 

  1. Flour

  2. Water (or other liquids such as juice, milk, yogurt, etc.)

  3. Two types of microorganisms: lactic acid bacteria and yeast (either airborne and/or present in the raw materials).

A sourdough starter is used as the leavening agent instead of commercial yeast when making sourdough bread. Doing this gives the bread an added and distinctive flavor. Depending on which sourdough starter is used, the final taste of the loaf can vary drastically.

This is because the flavor of sourdough depends, among other things, on the microorganisms present within it. These microorganisms within the sourdough can vary around the world. This allows bakers the opportunity to create a huge variety of flavor profiles through the use of different sourdough starters.

Where does sourdough come from?

The origins of sourdough can be traced back to ancient civilizations, where it was a staple food for many cultures around the world. 

One of the earliest records of sourdough dates back to around 3700 BCE in ancient Egypt. Archaeological evidence suggests the Egyptians used wild yeasts and lactic acid bacteria to ferment their dough, resulting in a lighter, more easily digestible bread¹. This leavened bread was a significant improvement over the dense and heavy flatbreads that were common during that time.


Puratos Sourdough Librarian, Karl de Smedt, holds a sourdough starter in front of the Puratos Sourdough Library.

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.

Puratos Sourdough Librarian, Karl de Smedt, holds a sourdough starter in front of the Puratos Sourdough Library.

Karl De Smedt - The Sourdough Librarian

Given that sourdough bread has been around for thousands of years, it’s even more remarkable that sourdough is likely to make up a significant portion of the future bread market. 

Our Taste Tomorrow research shows that consumers expect their baked goods to meet two out of three of the ‘Baked Goods Triangle’ criteria (fresh, healthy, and tasty). Sourdough bread has the potential to meet all three!

Is sourdough bread healthy?

Sourdough bread is considered healthier than other breads because it releases energy slowly and has been shown to be more easily digested than other breads. 

Sourdough bread has a low glycaemic index (GI), meaning it releases energy progressively over time instead of causing a sharp increase in blood sugar levels. When energy is released slowly in this way, we tend to feel fuller for longer, allowing us to control our appetite better. 

Sourdough bread is also more nutritious than the grain from which it is made. The fermentation process used in making sourdough helps release the nutrients and minerals in the bread and other foods (like cereals and legumes), making them easier to digest and more accessible to the body.

Is sourdough good for your gut?

Sourdough bread can contribute to a healthier gut microbiome due to its higher levels of beneficial lactic acid bacteria³. 

Studies have also shown that sourdough bread is easier to digest than other breads. This is because the ‘long fermentation’ process used in sourdough bread-making essentially begins digestion before we start eating it. 

(Learn more about the importance of long fermentation here: How Long Fermentation Is Changing The Baking Industry.)

In his 2019 study², Professor Marco Gabetti compared how easy it was to digest three different breads; one with just baker’s yeast, one with sourdough and baker’s yeast, and one with just sourdough.

The findings showed that sourdough-fermented breads are more digestible than those started with baker’s yeast alone.

It is important to note that, though an increasing number of studies show that the use of active living sourdough and long-time fermentation processes result in improved bread digestibility, a legally approved health claim isn’t accepted yet.

To find out more about the link between bread and digestibility, check out our blog article: Bread And Digestibility.


HoW to make sourdough

How to make a sourdough starter

Though there are many recipes to make sourdough starters of all kinds, to make a simple sourdough starter, all you need is flour and water. Here’s how to do it:

  1. Add 100 grams of water to a jar.
    Note: choose a glass Kilner jar, plastic container, or clay container. Avoid using any metallic containers for your sourdough starter. 

  2. Add 120 grams of flour to the water.

  3. Gently blend the flour and water. The mixture’s texture should resemble applesauce. Keep the sides of the jar clean, as it’s important to avoid leaving any dried pieces of starter on the sides.

  4. Leave your flour and water mixture at room temperature (between 20 and 35 degrees Celsius).

  5. Every 24 hours, repeat steps 1-4: Add 100 grams of water and 120 grams of flour, ensuring to keep the sides of the jar as clean as possible before leaving at room temperature. 

Over time, the sourdough will liquefy and bubble due to the increasing acidity. Don't get discouraged if it smells funky or unpleasant after a couple of days; that's when you must persevere. 

After five to seven days, depending on the type of flour used, your starter will be bubbly and slightly acidic when tasted.

You can measure the pH level to check your sourdough starter is ready to bake with. Your sourdough starter should have a pH level below 4.2. A pH below 4.2 eliminates any pathogens present in your starter. Once your starter meets these criteria, it is considered mature.

How to maintain a sourdough starter

To maintain your sourdough starter properly, there are a few key steps to follow. First, you need to store it in the fridge, preferably in a sealed container made of plastic or glass. This helps maintain its freshness and prevents any contamination. 

It’s important to keep your starter around room temperature. This ensures a favorable environment for the starter to thrive. It might become sluggish if the temperature is too low, while excessively high temperatures can also have adverse effects.

To preserve the starter, it is recommended to seal the jars tightly and not open them frequently. This allows the accumulation of CO2, which aids in its preservation. By following these steps, you can keep your starter viable for extended periods, even up to several weeks.

Taking a video or documenting its state is advisable if you plan to leave it longer, such as a few months. If any issues arise, you have a reference point to evaluate its condition and ensure it's still healthy.

How to make sourdough on an industrial scale

The growing popularity of sourdough bread has led many industrial bakers to explore how to capitalize on this trend. 

The most significant considerations to think about when mastering a rustic-style sourdough are:

  1. Achieving the ‘rustic look’
    Premium sourdough breads have a rustic look to the crust. This is the result of longer fermentation and higher hydration dough fermented with sourdough. Achieving the optimal ‘waxy’ texture and great-tasting bread requires the right processes and ingredients.

  2. Temperature and time control
    The longer you can ferment your sourdough, the more rustic bread characteristics you can create. It’s crucial to ensure you have the correct baking technologies to achieve this on a large scale.

  3. Using improvers
    Regardless of how premium your sourdough bread offering will be, improvers are necessary for the industrial process to raise the tolerance of the dough and keep the bread fresh and moist.

  4. Communicating the product
    Your packaging is of vital importance. Use it to tell your story and communicate the traditional aspects of the recipe.

A key consideration is to adapt your message to the local culture. 

Our research shows that different cultures have very different understandings of sourdough. Make sure to understand your audience and tweak your communication accordingly.


Sourdough recipes

Classic sourdough recipes

Traditional sourdough loaf

If you’re looking for a high-quality, classic sourdough, try this traditional sourdough bread recipe. Featuring our Sapore sourdough, this recipe delivers the ultimate rustic and hearty sourdough loaf.



Nordic sourdough bread

This rye and wheat sourdough loaf has a wonderful depth of dark and robust flavor. It features our Sapore sourdough range, which offers rich and complex fruity flavors. 

This recipe also uses Puratos Softgrain sourdough (infused with rye, sunflower, spelt, and linseeds) to complement and add extra flavor to the wheat and rye flour.



Sourdough croissants

Research in the Puratos ‘Quest for Sourdough’ project shows that sourdough lends itself well to laminated and other rich baked goods. 

Consumer taste tests found a preference for a ‘melting’ or ‘buttery’ croissant, both of which sourdough croissants deliver in spades!



Creative recipes using sourdough

Panettone with sourdough

The combination of the tangy sourdough starter and the sweet dried fruits creates an impeccably indulgent flavor. This recipe is easy to follow and will surely delight the final consumers.

According to our global Taste Tomorrow research, sourdough and panettone are the top-growing terms in the bakery world. Leverage this trend by offering this panettone creation to your customers.



Overnight sourdough croissants

Be prepared for the morning rush with this deliciously fluffy overnight sourdough recipe. 

They can be finished with our Sunset Glaze to give them an extra golden shine. 

Puratos Sourdough Products

Sapore sourdough range

Sapore sourdough range

The foundation of our Sapore range is based on fermentation that offers a natural, traditional, and differentiating taste and structure to finished baked products.  The range comprises various sourdough and other solutions to give your baked goods the best classic and high-quality sourdough texture and flavor.

O-tentic range

O-tentic range

In our O-tentic range, we’ve managed to capture the authentic flavor of the famous Altamura durum wheat sourdough bread. Easy to use and based on natural ingredients, O-tentic lets you produce various breads with one commonality: highly reminiscent of the good old days meaning tasty, fresh, and extremely high-quality.



Our Softgrain range offers the health of wholegrains combined with natural freshness and superior taste. Softgrain are tender sprouts, wholegrains, and seeds infused with sourdough. This combination delivers the fantastic health benefits of wholegrain with natural freshness and phenomenal flavor. Choose our Softgrain range if you want to deliver delicious baked goods that satisfy consumers' desire for healthy options.




1. Sourdough: A Recipe for the Microbial Ecology of a Kneaded Ecosystem by Nicholas A. Bokulich et al.

2. Rizzello, Carlo Giuseppe, et al. "Sourdough Fermented Breads are More Digestible than Those Started with Baker’s Yeast Alone: An In Vivo Challenge Dissecting Distinct Gastrointestinal Responses." Nutrients 11.12 (2019): 2954

3. Rezac et al., 2018