Bread Baking

AP Flour vs Bread Flour vs 00 Flour: Which to Use for Bread

Mariusz Lasak · May 8, 2026 · 12 min read

I baked the same sourdough recipe three times in one week using three different flours: King Arthur AP (11.7% protein), King Arthur Bread Flour (12.7%), and Caputo Pizzeria 00 (12.5%). Same hydration target, same starter, same kitchen temperature, same fermentation schedule.

The AP loaf was soft, slightly tighter crumb, easier to shape. The bread flour loaf had more chew, better oven spring, more open crumb. The 00 loaf was the most extensible, almost too soft for a freestanding loaf, but had a tender, light texture that would be perfect for a Neapolitan-style pizza or focaccia.

That experiment told me what numbers on a flour bag couldn’t: AP, bread, and 00 flour aren’t interchangeable. They behave differently because they’re built differently. Once I understood the why, picking the right flour became automatic, and substitutions stopped being guesswork.

What Actually Defines a Flour

The two variables that matter most

Flour is more variable than people realize. Two bags labeled “all-purpose” from different brands can behave like different flours entirely. Once you know what to look at, the picture clears up.

1. Protein content (10-14% range for wheat flours)

Protein content determines how much gluten the flour can form when mixed with water. Higher protein = stronger gluten = chewier, more elastic dough = better oven spring and structure. Lower protein = weaker gluten = more tender, softer baked goods.

This is by far the biggest variable. A 10.5% AP flour and a 13% bread flour will produce visibly and texturally different bread, even with identical recipes.

2. Grind fineness

The flour’s particle size affects how it absorbs water and how the dough feels. Finely ground flour (like Italian 00) absorbs water faster and produces smoother, more extensible dough. Coarser-ground flour (like American bread flour) absorbs more slowly and produces more elastic, structured dough.

Grind matters less than protein for most baking, but it’s the secret behind why 00 flour and bread flour at the same protein content still behave differently.

Other factors worth noting:

• Bleached vs unbleached: Bleached flour produces softer crumb and lighter color but slightly weakens gluten. Unbleached is preferred for artisan bread.
• Malted vs unmalted: Some flours include barley malt for enzyme activity, which speeds fermentation. Most American flours are malted; many European flours aren’t.
• Wheat type: Hard red wheat (high protein, used for bread flour), soft red wheat (lower protein, used for AP and pastry), durum (very high protein, used for pasta).

All-Purpose Flour: The Versatile Default

Medium protein, medium grind, designed for everything

All-purpose flour is the compromise flour. The protein and grind are calibrated to work passably for cakes, cookies, pancakes, biscuits, pizza, and bread, but it doesn’t excel at any single one.

Typical specs:

• Protein: 10-11.7% (varies by brand and region)
• Grind: Medium
• Hardness: Usually a blend of hard and soft wheat
• Color: Cream-white (unbleached) or bright white (bleached)

Brand variation is significant:

Note that “AP” in the southern US means something different from northern US. Southern AP (White Lily) is significantly lower in protein because it’s made for biscuits, using it for sourdough produces dense, soft, sandwich-style bread.

What AP flour does well:

• Cookies, cakes, pancakes, biscuits, scones (soft baked goods benefit from lower protein)
• Soft sandwich bread (mild chew, tender crumb)
• Pie crusts and pastries (less gluten = more tender)
• Casual same-day sourdough (works fine, produces softer crumb than bread flour)
• Roux, sauces, breading

What AP flour doesn’t do well:

• Long-fermented sourdough (gluten can break down over 12+ hour ferments with weaker AP)
• Bagels, pretzels, chewy artisan bread (lacks structure)
• Neapolitan pizza (wrong grind, wrong gluten characteristics)
• Pasta (needs durum or 00)

Bread Flour: Strength for Structure

Higher protein for chewy, well-risen bread

Bread flour is what most American sourdough recipes assume by default. The higher protein creates a stronger gluten network that holds gas better during long fermentation and produces better oven spring.

Typical specs:

• Protein: 12-13% (some brands go up to 14%)
• Grind: Medium (similar to AP)
• Hardness: Hard red wheat (high protein varieties)
• Color: Cream-white (most are unbleached)

Brand examples:

What bread flour does well:

• Sourdough (the default choice, handles long fermentation, produces open crumb)
• Bagels, pretzels, chewy artisan bread (high protein = high chew)
• New York style pizza (chewy, crisp, sturdy crust)
• Focaccia (good structure, holds shape)
• Sandwich bread when you want chew (deli-style rye, sourdough sandwich)

What bread flour doesn’t do well:

• Cakes, cookies, pastries (too tough)
• Tender quick breads (banana bread, muffins, scones)
• Neapolitan pizza (grind isn’t fine enough)
• Pie crust (too elastic, won’t be flaky)

The hydration adjustment:

Bread flour absorbs 2-3% more water than AP flour. So a recipe that calls for 65% hydration with AP flour translates to 67-68% with bread flour to match the same dough feel. Recipes written for bread flour at 75% hydration become 72-73% with AP flour.

00 Flour: The Fine-Grind Italian

Why grind fineness changes everything

00 flour confuses a lot of bakers. The “00” sounds like a strength rating but it actually refers to how finely the flour is milled. Italian flour grades go from 2 (coarsest) to 1, 0, then 00 (finest).

Typical specs (varies by type):

• Pizza-grade 00 (Caputo Pizzeria): 12.5% protein, very fine grind
• Pasta-grade 00 (Caputo Chef’s, similar): ~12-13% protein, very fine grind
• Cake/pastry 00: 9-10% protein, very fine grind

Why the fine grind matters:

The smaller particle size means flour particles hydrate faster and more evenly. This produces dough that’s:

• More extensible (stretches further before tearing)
• Smoother and silkier to handle
• Better at thin-stretching for pizza
• Less elastic, doesn’t snap back as much when stretched

Why protein still matters within 00:

A bag of pasta-grade 00 and a bag of pizza-grade 00 look identical but bake completely differently. Pasta 00 is bred for cake-like flour with low protein, using it for pizza produces dough that won’t hold together. Always check the protein content, not just the grade.

What 00 flour does well:

• Neapolitan pizza (the traditional choice, soft, extensible dough that stretches thin without tearing, see our Neapolitan pizza calculator for the matched dough math)
• Fresh pasta (the lower-protein 00 produces tender pasta)
• Focaccia (especially when you want very tender, soft crumb)
• Tuscan-style flatbreads
• Some cakes and pastries (the fine grind = soft texture)

What 00 flour doesn’t do well:

• Sourdough boules (too extensible, the loaf spreads more than rises)
• New York pizza (lacks the chew bread flour provides)
• Bagels, pretzels (protein is high enough but grind makes for less chew)
• High-hydration breads (gets sticky faster than bread flour at the same percentage)

Side-by-Side Comparison

All three flours at a glance

Which Flour for Which Bake

A practical guide by recipe type

Sourdough boule, batard, or sandwich loaf: Bread flour (12-13% protein). King Arthur Bread Flour is the safe default. AP works if it’s at least 11% protein (King Arthur AP at 11.7% is fine), but expect softer crumb and slightly less oven spring.

Neapolitan pizza: 00 pizza flour (Caputo Pizzeria or similar). The fine grind and protein balance produce dough that stretches thin without tearing, essential for the 3-minute bake at 700°F+.

New York or American-style pizza: Bread flour. The chew and structure handle a longer, lower-temperature home oven bake better than 00. King Arthur Bread Flour is excellent here.

Detroit or pan pizza: Bread flour or high-protein AP. Needs structure for the deep-pan rise.

Focaccia: Bread flour for chewy texture, or a 50/50 bread flour and 00 blend for tender, light texture. 00 alone tends to spread too much.

Bagels, pretzels, chewy buns: Bread flour, ideally 13%+ protein. King Arthur Bread Flour, Hodgson Mill, or specialty high-gluten flours.

Soft sandwich bread (white, milk bread, brioche): AP flour. The lower protein produces the soft crumb you want. Bread flour makes brioche too chewy.

Sourdough discard pancakes, muffins, cookies: AP flour. Bread flour makes them tough.

Pie crust: AP or pastry flour. Bread flour creates a tough crust.

Pasta: 00 pasta flour or semolina (durum wheat). Bread flour or AP is too elastic and not extensible enough.

Whole wheat or rye blends: Use bread flour as the base white flour. It compensates for the gluten-disrupting bran in whole grains.

How to Substitute Between Them

When you don’t have the right flour

You can substitute most of these flours for each other if you make the right adjustments. Here’s how.

Bread flour → AP flour:

• Reduce hydration by 2-3% (bread flour absorbs more water)
• Expect slightly tighter crumb and less oven spring
• Reduce bulk fermentation by 30-60 minutes, weaker gluten can’t sustain as long a ferment
• Works well: short-ferment sourdough, soft sandwich bread

AP flour → bread flour:

• Increase hydration by 2-3%
• Expect chewier texture and better oven spring
• Bulk fermentation can run 30-60 minutes longer if needed
• Works great: standard artisan sourdough

Bread flour → 00 flour (pizza grade):

• Roughly equal hydration, but expect more extensible dough
• Reduce starter percentage slightly to keep dough manageable
• Shape immediately after dividing, 00 dough relaxes faster
• Works great: Neapolitan-style pizza
• Doesn’t work well: tall freestanding loaves

00 flour → bread flour:

• Roughly equal hydration, but expect more elastic, springier dough
• For pizza, give the dough longer to relax before stretching (or it’ll snap back)
• Works fine: pizza will be chewier and less authentically Neapolitan

AP flour → 00 flour:

• Increase hydration by 2-3% (00 has more protein)
• Same as bread flour to 00, more extensible dough
• Works for: pizza, focaccia
• Skip for: sandwich bread (the result will be too soft)

Mixing for desired effect:

• 50/50 bread flour and AP: middle ground, good for soft-but-structured sandwich bread
• 75% bread flour, 25% whole wheat: classic country sourdough
• 80% bread flour, 20% 00: hybrid pizza dough that’s chewier than pure 00 but stretchier than pure bread flour
• 50% AP, 50% whole wheat: hearty rustic bread, lower protein offset by whole wheat fiber

Brand Notes Worth Knowing

Specific flours that matter

A few brand-specific things worth knowing, many sourdough recipes are tested with specific flours, and the brand matters as much as the category.

King Arthur Flour (US):

• AP: 11.7% protein, high for AP, behaves almost like a low-protein bread flour
• Bread flour: 12.7%, the benchmark most sourdough recipes assume
• Most reliable for consistent results, batch to batch

Caputo (Italy):

• Pizzeria (red bag): 12.5% protein, the Neapolitan pizza standard
• Chef’s (blue bag): 13% protein, more elastic, better for longer fermentation
• Cuoco (also red bag, Italian market): same as Pizzeria, marketed for restaurants

Bob’s Red Mill (US):

• AP: ~10-11% protein, softer than King Arthur AP
• Artisan Bread Flour: 12.5%
• Their AP behaves more like Southern US AP, softer crumb

Gold Medal / Pillsbury (US):

• Standard AP: ~10.5%, middle of the range
• Better for tender baked goods than for sourdough
• Both make decent everyday flour but underperform for artisan bread

Specialty bread flours (Central Milling, Lindley Mills, Hayden, etc.):

• Often 13-14% protein
• Usually freshly milled, sometimes with malt added
• Worth the price for serious sourdough, produces noticeably better results
• Some require small hydration increases (14% protein flour absorbs more)

Conclusion: Match the Flour to the Bake

AP, bread, and 00 flour aren’t just three names for the same thing. They have different protein levels, different grinds, and different behaviors, and the bread you bake reflects which one you used.

The good news: once you understand the differences, picking the right flour becomes automatic. Sourdough loaf? Bread flour. Neapolitan pizza? 00. Cookies and cakes? AP. Substitutions still work, just adjust hydration by 2-3% and accept slightly different texture.

Buy a digital scale and a small bag of bread flour for your next sourdough bake. If you’ve been using AP, the difference will be obvious, better oven spring, more open crumb, more chew. The flour change does work that no technique adjustment can match.

Frequently Asked Questions