Baking a sourdough starter with white flour or whole grain rye flour can result in different outcomes due to their distinct characteristics. While they can be used interchangeably to some extent, there are a few factors to consider:
Fermentation: Whole grain rye flour tends to ferment faster than white flour. This is because rye flour contains more natural sugars and nutrients, which can promote quicker fermentation. If you use whole grain rye flour in your starter, it may require more frequent feeding and attention to prevent it from becoming overly sour or acidic.
Flavor: Whole grain rye flour has a distinct flavor profile, which can impart a nutty and earthy taste to the sourdough bread. On the other hand, white flour has a milder flavor. The choice between the two will depend on the desired taste and aroma of your bread.
Gluten development: Gluten, a protein responsible for structure and elasticity in bread, develops differently in white flour compared to whole grain rye flour. White flour has a higher gluten content and produces a more elastic and chewy texture. Whole grain rye flour has less gluten and results in a denser and potentially more crumbly texture.
Absorption: Whole grain rye flour absorbs more water compared to white flour. When using whole grain rye flour in your starter or bread, you may need to adjust the hydration level by adding more water to achieve the desired consistency.
While you can use both flours interchangeably and mix them equally, it's important to consider the factors mentioned above. Experimentation with different ratios and techniques can help you achieve the desired flavor, texture, and characteristics in your sourdough bread.