All-purpose flours are generally a blend of hard and soft wheats, though this too may vary according to manufacturer and the tastes of the area they are producing it for.
|Canadian All-Purpose Flour||12.8 to 13.5 % (db)||0.45 to 0.51% (db)|
|American All-Purpose Flour||10 to 11.5%||0.45 to 0.51% (db)|
|British plain flour||7 to 10%||0.46% (db)|
(db) equals dry basis. Europe uses dry basis measuring, while North America tends to measure at 14% humidity. That being said, North American numbers will often give dry basis equivalents, so where possible those are used in order to be comparing apples with apples, as it were.
In American recipes calling for all-purpose flour, use plain flour in the UK. You may have to use a tidge more plain flour as plain flour is somewhat weaker than American all-purpose.
In Canadian recipes calling for all-purpose flour, you can substitute American all-purpose flour or UK plain flour except when the recipe is a bread recipe. Canadian all-purpose is a truly all-purpose flour, being very high in gluten, and can be used for bread, but American all-purpose and UK plain flour cannot. In America and the UK, if the recipe is a bread recipe calling for all-purpose flour or just white flour, you must use bread flour: Canadians can use all-purpose.
That being said, in America amongst home hobby bakers, there is a movement against using bread flour and for going back to using lower-protein American all-purpose flour for making artisanal breads.
In Germany, substitute type 405 flour when making cakes; type 550 flour when making breads.
1 pound = 3 ¾ cups unsifted = 4 cups sifted or pre-sifted
Though sometimes also referred to commercially as “enriched all-purpose flour”, that fuller term is now somewhat redundant as both all-purpose and plain flours are required by law in both the UK and North America to be enriched; you would be hard-pressed to find such flour that isn’t.