What's the difference between Bread Flour and All-Purpose Flour?

Bread Flour: 12.00-13.50% protein, absorption 1.000×, hydration 65-78%. All-Purpose Flour: 10.50-11.70% protein, absorption 0.970×, hydration 60-72%.

Can I substitute Bread Flour for All-Purpose Flour 1:1?

Not directly. Absorption differs by 3.1%, so Bread Flour needs more water. Adjust hydration by 3% when substituting.

Which is better for open-crumb sourdough?

Bread Flour supports higher hydration (up to 78%), making it better suited to open-crumb hearth loaves than All-Purpose Flour (max 72%).

Side-by-side comparison

Bread Flour vs All-Purpose Flour

	Bread Flour	All-Purpose Flour
Protein	12.00–13.50%	10.50–11.70%
Absorption (× bread flour)	1.000	0.970
Hydration range	65–78%	60–72%
Category	refined-wheat	refined-wheat
Ash %	0.50	0.48

Bread Flour

Bread flour is the workhorse of hearth-style sourdough. Milled from hard red winter or hard red spring wheat, it provides the 12-13.5% protein content needed to develop the robust gluten structure that supports open crumb and high hydration doughs. The absorption multiplier is the industry baseline (1.000) — all other flour hydration behaviors are measured relative to bread flour. King Arthur's classic unbleached bread flour and Central Milling's Artisan Bakers Craft are the reference specs for US bakers. Use it as 100% of the flour in baguettes and country loaves, or as the base (70-90%) in whole-grain blends. Bread flour tolerates extended autolyse, long bulk ferments, and retarded proofs without losing structure.

All-Purpose Flour

All-purpose flour (AP) sits between cake flour and bread flour in protein content. At 10.5-11.7% protein, it produces softer sourdough with more tender crumb but less oven spring than bread flour. Absorption is ~3% lower than bread flour baseline. King Arthur's AP is the US reference (11.7% protein); Gold Medal and Pillsbury run slightly lower (10.5-11%). Use AP when you want a softer hearth loaf, a sandwich-style sourdough pan loaf, or when blending into enriched doughs like brioche. AP absorbs less water — recipes designed for bread flour need hydration reduced by ~3% when substituting AP.

Substitution math

When substituting Bread Flour for All-Purpose Flour in a recipe, adjust hydration by about 3% — add more water because Bread Flour absorbs more than All-Purpose Flour.

The gear that makes the math work

A short, honest baking kit. The scale matters most — every weight on this page is in grams. The Dutch oven is what turns a good crumb into a great crust.

Digital kitchen scale (0.1 g)
Baker's percentage is by weight, not volume — a 0.1 g scale is what makes the math on this page accurate.
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Dutch oven / combo cooker
Traps steam for the first bake phase — the single biggest factor in oven spring and a blistered, glossy crust.
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Banneton proofing basket
Wicks moisture and holds shape during the final proof, so high-hydration dough doesn't spread flat.
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Bread lame + bench scraper
A sharp lame scores clean ears; a steel bench scraper handles wet, sticky dough without tearing the gluten.
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High-protein bread flour
The math assumes ~12–14% protein. Real bread flour absorbs the hydration you calculate — all-purpose won't.
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Danish dough whisk
Mixes shaggy, high-hydration dough in seconds without the gluey mess of a spoon or your hands.
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🎧 Or learn the craft by ear

The numbers here are the what; a good baking book is the why. An Audible trial gets you any title free — Michael Pollan’s Cooked(the “Air” chapter is the best story ever told about why bread rises) is a perfect first listen.

Start a free Audible trial →

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Gear guides — what actually matters