Sourdough starter is a fermented mixture of flour and water that is used as a natural leavening agent in bread baking. The type of flour used to maintain the starter can have a significant impact on the health and activity of the starter, as well as the final flavor and texture of the bread.

One of the most important factors to consider when choosing a flour for a sourdough starter is the protein content. Flours with a high protein content, such as bread flour or whole wheat flour, will typically produce a more active and vigorous starter.  Your sourdough starter feeds on the protein in the starer, producing more activity and gasses that aid in spring in the oven.  These flours are high in gluten, which is a complex protein that provides the structure and elasticity necessary for the fermentation process.  Flours with a lower protein content, such as all-purpose flour or pastry flour, may produce a slower-acting and less vigorous starter. These flours are lower in gluten, which means they will not provide as much structure and elasticity for the fermentation process.

Another important factor to consider is the type of grain used to make the flour. Different grains have different levels of enzymes and microorganisms that can affect the health and activity of the starter. For example, wheat flour is a common choice for sourdough starter because it is high in enzymes and microorganisms that promote fermentation. Rye flour is also a popular choice because of its unique flavor and high acidity, which can contribute to a more sour flavor in the bread.

Additionally, using different types of flour will also affect the final flavor and texture of the bread. Whole wheat flour, for example, will provide a nutty, earthy flavor and a denser texture to the bread. Whereas, using only all-purpose flour will result in a lighter, airier loaf.

The type of flour used to make a sourdough starter can have a significant impact on the health and activity of the starter, as well as the final flavor and texture of the bread. Choosing a flour with a high protein content and the right type of grain will promote a healthy and active starter, while also contributing to the desired flavor and texture in the final bread. Experimenting with different types of flour can be a fun and rewarding way to explore the many nuances of sourdough bread baking.