What is a starter?

A sourdough starter is a live culture of wild yeast and lactic acid bacteria that is used as a leavening agent in sourdough bread and other baked goods. It is a mixture of flour and water that has been allowed to ferment and capture naturally occurring microorganisms from the environment.

Here's a breakdown of how a sourdough starter works:

  1. Capture and Cultivate Wild Microorganisms: When flour and water are mixed together and left at room temperature, wild yeast and lactic acid bacteria present in the environment settle into the mixture. These microorganisms are responsible for the fermentation process.

  2. Regular Feeding: To keep the sourdough starter alive and active, it requires regular "feeding." This involves removing a portion of the starter and adding fresh flour and water. Feeding the starter provides new food for the microorganisms and removes waste products, ensuring the starter remains healthy and able to ferment.

  3. Fermentation: As the microorganisms in the starter feed on the carbohydrates in the flour, they produce carbon dioxide gas, as well as lactic acid and acetic acid. These acids give sourdough bread its characteristic tangy flavor. The carbon dioxide gas produced during fermentation causes the dough to rise, resulting in a light and airy texture.

  4. Use in Baking: When the sourdough starter is active and at its peak, it can be incorporated into bread dough recipes to serve as the leavening agent. Mixing the starter with flour and water in a bread dough allows the gas produced during fermentation to create bubbles and lift the dough, causing it to rise.

Sourdough starters can develop unique flavors and characteristics based on factors such as the type of flour used, environmental conditions, and the local microorganisms present. This diversity is why sourdough bread can vary in taste and texture from one region or baker to another.

Maintaining a sourdough starter requires regular care and attention to keep the microbial culture healthy and active. Many bakers value their sourdough starters for their ability to produce flavorful and distinctively textured bread!