How to Substitute Sourdough Starter for Yeast

One of the challenges I have taken up in the Czech Republic is making traditional Czech recipes. But substituting my sourdough starter for the more typically used commercial yeast. I have greatly enjoyed this challenge – and was able to produce some amazing results! This got me onto the idea that basically any recipe calling for yeast can be made using wild yeast! I just need to have a good conversion formula. In this post, I will share with you how to substitute sourdough starter for yeast in any recipe.

Difference between wild yeast & commercial yeast

Wild yeast and commercially produced yeast are two distinct types of microorganisms. They play a crucial role in the process of fermentation, particularly in the context of baking and brewing. Their differences lie in their origin, characteristics, and impact on the final product.

Wild yeast, as the name suggests, occurs naturally in the environment as a living organism. It can be found on the skins of fruits, in the air, and even on grains. This type of yeast is less predictable and more diverse in terms of strains. This can lead to variations in flavor, aroma, and fermentation speed. Capturing wild yeast for baking or brewing involves creating a starter or sourdough culture. Then, allowing the wild yeast to develop and establish itself over time. While this method embraces the unpredictability of nature, it requires more attention and experimentation to achieve consistent results.

On the other hand, commercially produced yeast is cultivated and manufactured under controlled conditions. It is selected from specific yeast strains that have been optimized for desired traits. Those are things such as fast and consistent fermentation, high CO2 production, and specific flavor profiles. Commercial yeast is available in various forms on grocery store shelves. This includes active dry yeast and instant yeast, and it offers reliability and convenience. Bakers and brewers can expect consistent results with a shorter fermentation period, making it suitable for mass production and standardized products.

Why use sourdough starter instead of commercial yeast?

Using sourdough cultures instead of commercial yeast offers several advantages that appeal to bakers and consumers alike. Here are some reasons why using a sourdough starter can be considered better in certain contexts:

Taste

Complex Flavor Profile: Sourdough starters are home to a diverse community of wild yeast strains and lactic acid bacteria. These microorganisms work together during fermentation. They produce a wide range of flavor compounds that contribute to a richer and more complex taste profile in the final baked goods. This depth of flavor is often missing when using commercial yeast, which tends to produce a more straightforward taste.

Distinct Aroma: The aromatic compounds created during sourdough fermentation can result in a more enticing and unique aroma in the finished products. This can be particularly appealing to those who enjoy the sensory experience of freshly baked bread with a characteristic tangy scent.

Digestion & Health

Improved Digestibility: The longer fermentation period involved in sourdough baking allows enzymes to break down gluten and other components in the flour. This can enhance the digestibility of the final product for individuals who are sensitive to gluten or have mild intolerances.
Lower Glycemic Index: Sourdough fermentation has been found to lower the glycemic index of bread, meaning it can lead to slower and more stable increases in blood sugar levels. This can be beneficial for individuals looking to manage their blood sugar levels.
Health Benefits: The presence of lactic acid bacteria in sourdough can promote the growth of beneficial gut bacteria, which may contribute to improved gut health and overall well-being.

Simplicity & Tradition

Artisanal Appeal: Sourdough baking is often seen as a craft that connects bakers to tradition and the natural processes of fermentation. It allows for a deeper understanding of the baking process and fosters a sense of accomplishment.
Minimal Ingredients: Sourdough starters require only flour and water to maintain, making them a simple and economical option for leaving bread and other baked goods. Commercial yeast may involve additional ingredients and processing steps.
Local Terroir: Using a sourdough starter cultivated from your local environment can create a unique link between your baked goods and the specific microbes present in your area. This can result in flavors and characteristics that are truly representative of your region.

Downsides of using commercial yeast

While commercial yeast offers convenience and consistency in baking, there are several downsides associated with its use that might influence bakers’ choices:

Flavor & Taste

Lack of Complexity: Commercial yeast ferments dough relatively quickly, which often results in baked goods with a simpler and less nuanced flavor profile compared to those made with natural fermentation methods like sourdough. The absence of the complex interactions between various wild yeast strains and bacteria can lead to a less distinctive taste.
Limited Aroma: The rapid fermentation process driven by commercial yeast might not allow sufficient time for the development of the aromatic compounds that create the characteristic and enticing smell of freshly baked bread found in slower, naturally leavened options.

Health Concerns

Digestibility Concerns: The accelerated fermentation caused by commercial yeast might not break down gluten and other components in the same way as natural fermentation does. This could potentially impact the digestibility of the final product, causing discomfort for individuals with mild gluten sensitivities.
Glycemic Impact: Baked goods leavened with commercial yeast can have a higher glycemic index, leading to quicker spikes in blood sugar levels. This can be a concern for individuals aiming to manage their blood sugar.
Health Considerations: Some studies suggest that the rapid fermentation process associated with commercial yeast might not allow enough time for the breakdown of antinutrients present in flour. This could potentially hinder the absorption of certain nutrients in the digestive tract.

Other

Uniformity Over Uniqueness: The use of commercial yeast often leads to standardized baked goods, which can lack the individuality and artisanal charm of those created through natural fermentation methods. Bakers seeking to create distinctive products might find this limiting.
Dependence on Supply: Relying on commercially produced yeast can create a dependency on external sources and suppliers. In situations where access to commercial yeast is disrupted, bakers might face challenges in continuing their regular baking practices.
Environmental Impact: The production of commercial yeast involves industrial processes that consume energy and resources. Opting for natural fermentation methods like sourdough could be considered more environmentally friendly.
Chemical Additives: Some commercial yeast products contain additives such as preservatives and emulsifiers, which might not align with a preference for simple and natural ingredients.
Loss of Tradition: Using commercial yeast might distance bakers from the traditional methods of fermentation that have been passed down through generations. It can reduce the connection to the heritage and artistry of baking.

How to substitute sourdough starter for yeast

To substitute sourdough starter as the leavening agent for yeast requires a few small adjustments to the recipe you’re making. As a general rule, if you can find the original recipe you’re making as a sourdough recipe, always opt for that. It has (hopefully) already been tested and you’re guaranteed success. That being said, I have come across numerous recipes, especially Czech food recipes, that still call for commercial yeast and a sourdough version is nowhere to be found. In those cases, I have used the following formula and the recipe always turned out to be a success:

Use 100g of sourdough starter to replace 1 packet of yeast (usually 7g)
Reduce the liquid and flour weights the recipe calls for by 50g each
Add the sourdough starter at the time the recipe calls for yeast. Proceed with mixing & kneading.
Allow time for bulk fermentation and proofing as you usually would with other sourdough recipes.

Example of converting a recipe from yeast to sourdough

One of my favorite recipes that I recently used to substitute converted from regular yeast to sourdough starter was this Blueberry Kolace recipe.

It calls for:

250g all purpose flour
125ml milk
10g yeast
30g sugar
2 egg yolks
lemon rind
100ml oil

Using the formula above, I cut down on the amount of flour and amount of water, used sourdough starter in place of yeast, and got the following:

200g flour
100g milk
120g sourdough starter
20g sugar (I wanted the recipe less sweet)
2 egg yolks
lemon rind
85ml oil

Substituting sourdough starter for yeast tips

The amount of liquid and flour will always differ slightly, based on the hydration levels of your starter. I have found it helpful to roughly know what the dough consistency of what you’re making is supposed to be and adjust the flour & water as you go to reach the desired consistency

If you don’t have your own sourdough starter going or would like tips on how to make it, check out THIS POST

Rising time will depend on your room temperature (or the temperature you set in your proofing box, if using)

When using a different flour than what the recipe calls for (for example whole wheat flour instead of white bread flour, you will have to further adjust the grams of water used

It is very helpful to have at least a rough idea of what the dough consistency is supposed to be like, so that you can adjust the parts water and flour further, if needed

Substituting Sourdough Starter for Yeast FAQ

How do I create a sourdough starter?

I have a whole post that walks you through the process. You can find a detailed sourdough starter recipe here and here. In summary, you add a cup of flour and a cup water into a jar and stir. Every day you remove a cup of starter (this is commonly called sourdough discard). Then feed your starter with equal parts water and flour. After a couple weeks, you will have an active sourdough starter. It can be mature enough for sourdough bread recipes.

To determine whether your starter is mature enough for homemade sourdough bread baking, you can conduct something called the “float test”. This is done by placing a small teaspoon of starter in a glass of water. If the starter floats to the top (indicating a sufficient amount of carbon dioxide bubbles which are a bi-product of fermentation) then you’re good to go! If the starter sinks to the bottom, you should continue feeding it. Cup flour and cup of water at a time, keep it in a warm place, and monitor when it starts to double on a regular basis. You can use a rubber band on the outside of your starter jar to track the rise.

Can I use this formula in bread dough?

I personally have not tried to substitute sourdough starter in a yeast bread recipe. I usually opt for a sourdough bread recipe instead. My favorite bread recipe is this one. It has simple ingredients and creates delicious bread.

I am sure that you can find a sourdough version of the bread recipe you’re trying to make. They are so widespread these days. Even when it comes to making bread in a bread machine, quick breads or sweet bread recipes. If you absolutely cannot find as sourdough alternative to the regular yeast bread you’re trying to make, the formula above should work just fine too.

How to make any yeast recipe with sourdough starter

Difference between wild yeast & commercial yeast