How to Replace Yeast with Sourdough Starter: Step-by-Step Guide

If you have ever wondered how to replace yeast with a sourdough starter or turn a yeast recipe into a sourdough one, there is a rewarding way to do it. Using sourdough starter instead of yeast not only changes the way your baked goods taste but also boosts their health benefits.

However, this is not just a simple swap. Think of it as a sourdough challenge. Things like proofing time, dough texture, and flavor will differ from recipes that use commercial yeast.

For a full guide on the differences, pros, and cons, check out my Yeast vs. Sourdough Starter blog post.

How much sourdough starter to use in place of yeast

The general rule is to use 100 grams of mature sourdough starter to replace one packet (5-7 grams) of instant yeast.

Why is substituting sourdough starter for yeast so special?

A sourdough starter is a mixture of wild yeast and bacteria that causes the dough to rise, as commercial yeast does. Swapping yeast for a sourdough starter not only adds a tangy flavor to bread but also makes it healthier.

But sourdough takes longer to ferment. Instead of 1-2 hours of proofing with yeast, it requires 6-8 hours (sometimes longer) of bulk fermentation at room temperature, followed by an overnight cold proof.

If you include the time needed to make the levain, the entire process takes up to almost three days.

Also, when substituting sourdough starter for yeast, you need to consider your starter's hydration and adjust the other ingredients in your recipe accordingly.

How to replace yeast with sourdough starter

To replace yeast with sourdough starter, follow these steps:

• Swap one packet of yeast (5-7 grams) with 100 grams of active sourdough starter.

• Next, adjust the hydration of your recipe. If you use a 100% hydration starter, subtract half its weight from the flour and liquid in the original recipe. For example, if you use 100g of 100% hydration starter (1 part water to 1 part flour), subtract 50g of flour and 50g of liquid from the recipe.

• Then, allow extra time for the dough to ferment. Sourdough works more slowly than commercial yeast, so your proofing time will be much longer, though the baking time stays the same.

If you use more or less than 100 grams of sourdough starter, remember to adjust the flour and water amounts accordingly. Using more starter will speed up bulk fermentation, but it can make the dough sticky and harder to work with.

Example: French brioche

Here is how to convert a French brioche recipe, using commercial yeast, into a recipe with the sourdough starter.

Original recipe:

• 260g whole milk
• 70g grapeseed oil
• 10g vanilla sugar
• 380g all-purpose flour
• 60g granulated sugar
• 5g salt
• 7g instant dry yeast 

To make the switch, first ask yourself a few questions: What is the amount of yeast in the original recipe? How much flour is called for in the original recipe? How much water is used in the original recipe?

To convert this to sourdough:

• Replace the 7g of yeast with 100g of 100% hydration sourdough starter.
• Subtract 50g of flour and 50g of milk to balance the added starter.

Converted recipe:

• 260g whole milk >> 210g milk
• 70g grapeseed oil
• 10g vanilla sugar
• 380g all-purpose flour >> 330g all-purpose flour
• 60g granulated sugar
• 5g salt
• 7g instant dry yeast >> 100g 100% hydration active starter

FAQ

Can you replace baking powder or baking soda with sourdough starter?
No. Baking powder and baking soda give an instant rise, while sourdough requires time to ferment.

Can you substitute sourdough starter for yeast without changing other ingredients?
Not entirely. Sourdough starter affects the water-to-flour ratio, so you will need to adjust those amounts to keep the recipe consistent.

Can you use sourdough starter instead of fresh yeast?
Yes. Keep in mind that 7 g of instant dry yeast equals 21 g of fresh yeast, and you will also need to adjust the water and flour amounts in your recipe.

Let's talk sourdough

Have you ever swapped yeast for a sourdough starter? What recipes did you try, and how did they turn out? Share your experiences in the comments below.

Ready to keep learning?

While using your starter for baking, don't forget about the discard. Learn creative ways to add sourdough discard to any recipe without waste.