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The Best Flour for Sourdough: A Buyer's Guide

Bread flour, all-purpose, whole wheat, rye — which to buy and when. A practical guide to choosing flour for great loaves.

Ben Holloway2 min read

The best all-around flour for sourdough is unbleached bread flour (12–14% protein), which provides the gluten strength for good structure and oven spring — with whole wheat or rye added in small amounts for flavor and fermentation. Your flour choice affects everything: rise, crumb, flavor, and how the dough handles.

Flour types at a glance

FlourProteinBest for
Bread flour12–14%Everyday loaves, structure
All-purpose10–12%Softer crumb, beginner-friendly
Whole wheat~13–14%Flavor, nutrition (thirstier)
RyeLow glutenFlavor, faster fermentation
Spelt/einkornVariableAncient-grain flavor, delicate

Why protein matters

Protein content determines gluten potential. Higher protein = stronger gluten = better gas retention and oven spring. Bread flour's higher protein is why it makes taller, chewier loaves than all-purpose. For artisan sourdough, bread flour is the reliable default.

A practical strategy

  • Base: 80–90% bread flour for structure.
  • Flavor: 10–20% whole wheat, rye, or spelt for depth and to feed fermentation.
  • Adjust hydration: whole grains drink more water (add 3–10%).

What to buy

  1. A good unbleached bread flour — your workhorse.
  2. Whole wheat flour — for blending and nutrition.
  3. Rye flour — a little goes a long way for flavor and starter health.
  4. Optional: high-extraction or specialty flours as you advance.

Bleached vs. unbleached

Use unbleached flour. Bleaching uses chemical treatments that can interfere with flavor and fermentation. Unbleached flour ferments and tastes better.

Fresh vs. stored

Flour is best fresh. Store it airtight in a cool, dark place; whole grain flours go rancid faster (their oils oxidize), so buy them in smaller amounts or refrigerate/freeze them.

Frequently asked questions

Can I make sourdough with all-purpose flour?

Yes — it works, especially for beginners, though loaves are a bit less structured than with bread flour.

Is organic flour better?

Not necessarily for performance, but many bakers prefer it for flavor and fewer treatments. Quality varies by brand more than by label.

What flour is best for feeding my starter?

Whole wheat or rye for vigor (more nutrients and wild yeast), or white flour for a milder culture. Many keep their starter on a rye/white blend.

The right flour is the foundation of a good loaf. SourdoughAI adjusts hydration and timing for whichever flour you use, so swapping flours doesn't wreck your bake.