The difference is protein. Bread flour usually carries around 12 to 14% protein, while all-purpose flour sits somewhere between about 9.5 and 11.7%, depending on the brand and the country. More protein means more gluten, which gives a dough more strength and stretch, a loaf more height and a crumb more chew, and it lets the flour absorb a little more water. For most everyday bread you can use either one and still get a good loaf. The difference shows most in bagels, pizza, tall tin loaves and wet sourdough, and you can close the gap by adding a little vital wheat gluten to all-purpose flour.
Going the other way is a different story. Bread flour in cakes, cookies and pastry tends to make them tougher and chewier, so all-purpose remains the better choice there.
What the protein figure tells you
Bread flour is milled mainly from hard wheat, which is high in the proteins that form gluten. All-purpose flour blends in softer wheat so it can handle both bread and cakes reasonably well. The protein percentage on the bag is the easiest way to compare them. If the bag only has a nutrition panel, compare the protein with the serving size: 3 g of protein in a 30 g serving means 10%.
Names vary more than you might expect:
- United States. All-purpose flour commonly runs from about 10 to 11.7% protein. Bread flour is usually 12 to 13%, and high-gluten flour for bagels and pizza goes to 14% or more.
- United Kingdom and Ireland. Plain flour is often around 9 to 10%, meant for cakes and pastry. Strong white flour is the bread flour, typically 12 to 13% or a little higher.
- Canada. Many all-purpose flours are milled from hard wheat and already list 12 to 13%.
- Continental Europe. Flours are graded by fineness and mineral content, such as Italian 00 or German type 550, rather than by protein, so the label is the only reliable guide.
How each one behaves in dough
Strength and rise
Gluten traps the gas that yeast produces. A stronger network holds more of it and stretches further before tearing, so a bread flour dough rises taller, holds a sharper score and keeps its shape better on the counter. An all-purpose dough of the same recipe is softer and slacker, spreads a little more and bakes into a slightly lower loaf with a more tender crumb.
Water
Protein absorbs water, so bread flour takes a bit more. A dough that feels just right at 70% with bread flour can feel sticky and loose with all-purpose. When you swap in the weaker flour, hold back a little of the water and add it only if the dough feels firm.
Texture and colour
Bread flour gives a chewier bite and a slightly more open crumb, which is what you want in a bagel or a crusty loaf and exactly what you don’t want in a birthday cake. Its extra protein also browns a little more readily, so bread flour crusts tend to colour slightly deeper at the same temperature.
Which flour for which bake
- Bread flour: bagels, pretzels, crusty sourdough, high-hydration loaves, New York-style pizza, and tin loaves meant to stand tall.
- All-purpose flour: cakes, cookies, muffins, pancakes, pie and tart pastry, quick breads and scones.
- Either works: focaccia, soft dinner rolls, flatbreads, basic sandwich bread and most enriched doughs, where butter, milk and sugar soften the crumb anyway.
Pizza depends on the style and the oven, which Neapolitan vs New York pizza dough goes into.
Using all-purpose when a recipe wants bread flour
You have two options. The simple one is a straight swap with slightly less water, accepting a softer loaf. The precise one is to raise the all-purpose flour’s protein to match with vital wheat gluten, which is nearly pure wheat protein.
Here is how much gluten it takes. A recipe needs 600 g of bread flour at 12.7%, and your all-purpose bag lists 3 g of protein per 30 g serving, which is 10%. The bread flour substitute calculator returns 575 g of all-purpose flour and 25 g of vital wheat gluten, with the mix at 12.7% protein and the gluten making up 4.15% of it. The total stays at 600 g, so the water, salt and yeast in the recipe need no change.
With a stronger American all-purpose flour at 11.7%, the same recipe needs only 591 g of flour and 9.5 g of gluten. And if your all-purpose bag already says 13%, as some Canadian flours do, the calculator tells you it can be used exactly as it is.
Whisk the gluten thoroughly into the dry flour before any liquid goes near it, and expect the dough to feel a touch firmer than an ordinary all-purpose dough.
Blending the two
Sometimes the question is how far a small amount of bread flour will stretch. Say you have 360 g of bread flour at 13% left and plenty of all-purpose at 10.5%, and your recipe needs 600 g of flour. You would like the blend to land at 12%. In the flour protein blend calculator, choose weights for a target protein and enter the two flours: it asks for 240 g of all-purpose and 360 g of bread flour, exactly the bread flour you have. The blend makes a loaf that is noticeably stronger than all-purpose alone.
Blending also works in reverse. Cutting bread flour with all-purpose softens a sandwich loaf or a batch of rolls without buying another bag.
Flour choice in sourdough
Long fermentation changes the picture a little. Over many hours, the acid and enzymes in a sourdough gradually loosen the gluten, so a dough that felt strong after mixing is noticeably softer by the time you shape it. A stronger flour gives you more margin: it holds up better through a long bulk, a cold proof and a high hydration.
That doesn’t rule out all-purpose flour. Sourdough made with it works well at a slightly lower hydration, around 68 to 70% true hydration rather than 75% or more, with an extra set of folds and a bit less time in the fridge. The sourdough hydration calculator shows where a recipe lands once the starter’s water is counted, which is the figure to compare when you change flours.
Common flour mix-ups
- Assuming every brand is the same. Two flours sold under the same name can differ by a percentage point or more of protein. Read the label.
- Using bread flour for cakes and cookies. Expect a chewier, tougher result than the recipe intends.
- Swapping flours without touching the water. Weaker flour needs a little less, stronger flour a little more.
- Blaming the flour for every flat loaf. A slack dough is far more often underfermented than underpowered; why is my sourdough dense? covers the usual causes.
- Measuring by the cup when comparing flours. Different flours pack differently, so weigh them; why bakers weigh ingredients shows how much cups can drift.
Flour questions
Is strong flour the same as bread flour?
Yes. Strong white flour is the British name for bread flour, and very strong flour is closer to American high-gluten flour.
Is plain flour the same as all-purpose flour?
Roughly, but British plain flour is often a little lower in protein than American all-purpose. It is ideal for cakes and fine for many breads, though a loaf made with it will be noticeably softer.
Does bread flour make sourdough more sour?
No. Sourness comes from fermentation time, temperature and the starter, not from the flour’s protein. Whole grain flours can add a little extra tang, but white bread flour and all-purpose behave much the same in that respect.
When is high-gluten flour worth buying?
If you bake bagels or New York-style pizza often, its extra chew is noticeable. For everyday loaves, ordinary bread flour is plenty.