The best flour for sourdough depends on the type of bread you're making, but generally, a combination of high-protein bread flour and whole grain flour (like whole wheat or rye) works best. Here’s a breakdown:

1. Bread Flour (Best for Strong, Open Crumb)

• Protein Content: ~12-14%

• Why? The high gluten content provides structure and helps trap gas, leading to a better rise and airy crumb.

• Best for: Classic sourdough with an open, chewy texture.

2. Whole Wheat Flour (Adds Flavor & Nutrients)

• Protein Content: ~13-15%

• Why? Adds depth of flavor, nutrients, and a slightly denser crumb.

• Best for: Heartier, more rustic loaves (often used in a mix with bread flour).

3. Rye Flour (Boosts Fermentation)

• Protein Content: ~8-12% (but lower gluten)

• Why? Rye contains more amylase and nutrients, which can make your starter more active.

• Best for: Tangy, moist sourdough (often used in small amounts, 10-20%).

4. All-Purpose Flour (Versatile but Weaker Rise)

• Protein Content: ~10-12%

• Why? Works in a pinch but may produce a less open crumb.

• Best for: Beginner bakers or softer sandwich loaves.

Recommended Blend for Classic Sourdough:

• 80% Bread Flour (for strength & rise)

• 20% Whole Wheat or Rye (for flavor & fermentation)

Tips:

• Freshly milled whole grain flour can enhance flavor and activity.

• Avoid bleached flour—it lacks the nutrients sourdough microbes need.

• Experiment! Different flours change texture, taste, and fermentation speed.