What Is Sourdough Bread?

Updated: Dec. 05, 2023

A sliced loaf of homemade sourdough bread.

Taste of Home

What is sourdough bread, exactly? Here's what separates this fermented loaf from other types of yeast breads.

It’s hard to beat the aroma of freshly baked bread, especially when it’s the sweet tang of sourdough. This crusty bread has seen a recent surge in popularity—but what is sourdough and why is it so tasty? The bread has an airy texture and a distinct flavor—here’s what sets sourdough apart from other types of bread.

The History of Sourdough Bread

Bread has been around longer than many other foods, and sourdough has been around longer than most other breads—although the term “sourdough” is a newer one.

Sourdough got its start before commercial yeasts and mass production were introduced in the 19th century. Traditional recipes contained a starter, salt and flour. Although this recipe sounds fairly plain, it produces the complex, pungent flavor of sourdough that we know and love.

(Our Test Kitchen answered your burning questions about how to use sourdough starter.)

Why Is Sourdough Bread Different?

A person kneading sourdough to make a loaf homemade sourdough bread. Taste of Home

Unlike other yeast bread recipes that use baker’s yeast as the leavening agent, traditional sourdough recipes use a starter made of water and flour. The starter ferments over time, producing natural yeast and the slightly acidic flavor that sets sourdough apart. Sourdough bread is also known for its crusty yet airy texture.

Although sourdough bread can be relatively easy to make, it can be intimidating for new bakers because it’s more time consuming than other types of homemade bread. It’s often made by hand (instead of in a bread machine), which gives it a rustic quality.

What Makes Sourdough Sour?

The sourness of the bread comes from the acids produced in the starter. The ingredients, plus a warm environment, create a perfect storm for the starter to ferment and take on that signature sour flavor.

If you’d like to make a more sour loaf, find a cool spot for the dough to rise. Or, when mixing the starter, use a higher ratio of flour to water.

The Science of Sourdough

A mason jar full of bubbly sourdough starter. Taste of Home

The sourdough fermentation process happens as two naturally-occurring components of flour—yeast and lactobacillus (a type of healthy bacteria)—combine and grow over time. (Here’s how to make a quick sourdough starter, step by step.)

This bubbly starter mixture ferments for several days. It requires regular “feedings” of additional flour and water, which increase its volume. When you’re ready to use your starter, you add it to bread dough and let it rise—this produces bread that has a crusty outside and chewy inside with plenty of air pockets.

Part of the sourdough process involves “discarding” part of your starter before feeding it. You can use that excess starter to make other things, like these sourdough discard recipes.

How to Make Sourdough Bread

It’s relatively easy to make your own sourdough bread at home. First, you need to make a sourdough starter (or get one from a friend). You can make a traditional starter with just flour and water (as well as patience, while those two ingredients produce natural yeast over time). However, our sourdough starter recipe uses active dry yeast to help speed the process along.

Once your sourdough starter is ready, combine it with the rest of your bread ingredients according to the recipe’s directions. There are many different sourdough bread recipes with slightly varying methods. For instance, this no-knead sourdough bread recipe uses active dry yeast to create a sourdough starter in just 48 hours.

Our Test Kitchen’s favorite sourdough loaf recipe uses a mix of sourdough starter made with active dry yeast as well as additional active dry yeast to ensure an easy rise. Our step by step guide to how to make easy sourdough bread is based on this recipe.

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