What's he difference between all-purpose-flour and regular flour?

Bread flour is a high-gluten flour that has very small amounts of malted barley flour and vitamin C or potassium bromate added. The barley flour helps the yeast work, and the other additive increases the elasticity of the gluten and its ability to retain gas as the dough rises and bakes. Bread flour is called for in many bread and pizza crust recipes where you want the loftiness or chewiness that the extra gluten provides. It is especially useful as a component in rye, barley and other mixed-grain breads, where the added lift of the bread flour is necessary to boost the other grains.

All-purpose flour is made from a blend of high- and low-gluten wheats, and has a bit less protein than bread flour — 11% or 12% vs. 13% or 14%. You can always substitute all-purpose flour for bread flour, although your results may not be as glorious as you had hoped. There are many recipes, however, where the use of bread flour in place of all-purpose will produce a tough, chewy, disappointing result. Cakes, for instance, are often made with all-purpose flour, but would not be nearly as good made with bread flour.

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There is no such thing as "regular flour". Flours, by the way, are classed according to their protein content. Bread flour has the highest protein content, all-purpose has a middle-range protein content and pastry flour has the lowest protein content. There are also flours that are not made out of wheat and there are many more flours that I did not mention. However, home cooks are generally not concerned with other types of flour. Usually only bake shops use the other types.

If you have a recipe calling for regular flour, just use all-purpose flour.

Regular flour is all purpose flour.

They are the same identical thing. All-Purpose Flour is it's formal name.

We call it regular.....our slang for All-Purpose flour

All purpose flour is just regular plain flour with no levening in it meaning that if you use this type of flour, you'll need to add baking powder and baking soda for it to rise.

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