A jar of matured sourdough starter.

How to Convert a Yeast Recipe to Sourdough

Can you convert a yeast recipe into a sourdough recipe? Although it may seem intimidating at first, making the switch is easier than you might think. Many of your favorite yeast-leavened recipes can be successfully converted to sourdough and with our easy-to-follow guide, you’ll learn how you can make the switch with just a few simple adjustments.

Transform Your Yeast Bread into Sourdough: A Step-by-Step Guide

Example Recipe we will be working with:

  • 4 cups flour
  • 1 ½ cups water
  • 2 tsp salt
  • 1 ½ tsp yeast

Step 1: Remove Yeast as an Ingredient

Remove the yeast from your recipe. The new ingredient list will look like this:

Example Recipe:

  • 4 cups flour
  • 1 ½ cups water
  • 2 tsp salt

Step 2: Work in Weight

If your recipe is written in volume (cups and teaspoons), the next step is to convert it to weight. We recommend working in grams for accuracy. If your recipe is already in grams, you’re ready to move on to the next step.

Example Recipe:

  • 4 cups flour = 500g
  • 1 ½ cups water = 350g
  • 2 tsp salt = 10g

Step 3: Decide on the Starter Amount

Decide how much sourdough starter you want to use. A good starting point is 15-20% of the flour weight.

Example:

For a recipe with 500g of flour, using 18% starter means you’ll need 90g of starter.
Calculate this by multiplying the flour weight by the percentage you choose → 500g x 0.18 = 90g of starter.

Step 4: Adjust the Liquid and Flour

Since the sourdough starter is made up of flour and water, when you use it to replace packaged yeast, you add extra flour and water to the recipe. You'll need to subtract an equivalent amount of flour and water from the original ingredients to ensure that you stay true to the original recipe's proportions.

Most people use a 100% hydration starter, meaning the starter contains equal parts flour and water by weight. (Hydration level refers to the percentage of water relative to the flour in the starter. A 100% hydration starter means the water weight equals 100% of the flour weight—in simple terms, they weigh the same.)

For example, if you have 100g of starter, it would consist of 50g of flour and 50g of water.

In our example, 90g of starter consists of 45g of flour and 45g of water. Subtract these amounts from the original recipe:

  • 500g flour - 45g = 455g flour
  • 350g water - 45g = 305g water

The Adjusted Recipe:

  • 90g sourdough starter
  • 455g flour
  • 305g water
  • 10g salt
What if my starter is not 100% hydration?

If your starter has a different hydration level, you’ll need to determine how much flour and water it contains. The goal is to keep the original amounts of flour and water the same even after incorporating your sourdough starter.

For example, if you maintain a stiff starter (which has more flour than water), a 50% hydration starter has half the amount of water as it does flour. This means the water weight equals 50% of the flour weight.

In our example, 90g of a 50% hydration starter consists of 60g of flour and 30g of water. Subtract these amounts from the original recipe:

  • 500g flour - 60g = 440g flour
  • 350g water - 30g = 320g water

The Adjusted Recipe:

  • 90g sourdough starter
  • 440g flour
  • 320g water
  • 10g salt

Note: If your recipe uses milk instead of water, you can subtract the starter’s water weight from the milk amount.

Step 5: Adjust Fermentation Times

Sourdough takes longer to ferment than non-sourdough. You will need to increase the time for both the bulk fermentation (first rise) and the final proof (second rise).

The Bulk Fermentation:

The length of time will depend greatly on your dough and the temperature at which it is kept. In general, most yeast dough needs 1-2 hours for the first rise. Sourdough will need roughly 3-4 times as much time to rise. The lower the percentage of starter added to the dough, the more time it will need to rise, and vice versa. From our example recipe above, we are using 18% starter, if we kept the dough temperature at 78-80°F, we’d expect the dough to need about 4 hours for bulk fermentation. Again, many factors can impact the rate, and this is just a guideline.

The Final Proof:

The timing of the final proof (second rise) will also need to increase. Because fermenting sourdough is time-intensive, bakers often do a cold final proof overnight in the refrigerator. After shaping, the dough is placed in either a bread pan or banneton and then into the refrigerator overnight to be baked the next day.

Alternatively, the dough can be baked on the same day. After shaping, the dough will need to rise for approximately twice the time that yeast dough would take. If the final rise for yeast dough is 1-2 hours, the sourdough will probably take 2-4 hours.

Converting a yeast recipe to sourdough may seem challenging at first, but with a few adjustments and some patience, you can enjoy the unique flavors and textures that only sourdough can offer. Remember, every sourdough journey is a bit of an experiment, so don’t be afraid to tweak and refine your process as you go. Whether you’re looking for a tangy twist on a classic or simply want to explore natural leavening, converting your favorite yeast recipes is a rewarding way to deepen your baking skills.

Related Article: Maintain Your Sourdough Starter like Never Before with the Sourdough Home Related Article: Sourdough Starter 101