How is cake flour different from pastry flour? What makes bread flour and all-purpose flour distinct? Can you substitute one type of flour for another? If so, how? We sifted through the details to find out the answers to these questions and more.

By Mindy Fox

Cake flour, bread flour, pastry flour, and all-purpose flour (which are all made from wheat) vary primarily by the type of wheat they’re made from and their protein content, which is perhaps the most interesting and certainly the most significant difference between them, especially when it comes to baking.

Protein content determines how much gluten the flour will form, which in turn affects the textural quality of your baked good. Flours with a high protein content create more gluten (which provides a strong and dense structure), and those with a lower protein content form less gluten (lower protein and less gluten gets you light and airy structure; think ‘LLL’ for Lower protein. Less gluten. Light texture.). Let’s take a closer look at each of these four flours, from high to low protein content, and chat about best uses and substitutions.

Bread Flour

With a protein content of approximately 14 to 16 percent, this high-gluten flour is a blend of 99.8 percent hard-wheat flour with a touch of malt barley added to improve yeast activity, plus vitamin C or potassium bromate, which increases gluten’s elasticity. In short, it’s your go-to flour for yeast breads, which are breads that use yeast as a leavening agent (brioche, croissant, French bread and sourdough, for example).

Can you substitute all-purpose flour for bread flour (and vice-versa)? Yes, you can absolutely make a 1:1 substitute. For 1 cup bread flour, use 1 cup all-purpose, and vice-versa (note breads and pizza crusts made with all-purpose flour may have a little less chew than those made with bread flour, but results will still be good). If you want to try using bread flour as a substitute for all-purpose flour in recipes for yeast doughs that call for all-purpose flour, your breads and pastries will get a welcome extra little lift. You can try using bread flour as a substitute for all-purpose in our No-Knead Onion Rolls, Basil Beer Bread, or Foolproof Whole Wheat Bread.

All-Purpose Flour

This is the flour you probably know very well and (unless you are gluten-intolerant) likely love. Made from a blend of high-gluten hard wheat and low-gluten soft wheat, it’s terrific for everything from our favorite Buttermilk Pancakes, Sugar Cookies, and Classic Chocolate Layer Cake, to dredging chicken for Oven Baked Chicken Tenders or Hot Chicken Tacos with White Slaw Sauce, and more.

All-purpose flour (or AP Flour, as it’s known in chef speak) is a fine-textured flour with an approximate protein content of 10 to 12 percent. This flour comes in two forms, bleached (which is flour that is bleached by a chemical process) and unbleached (which is flour that is actually bleached, but it’s bleached naturally as it ages). Generally speaking, recipes that call for all-purpose flour are best made with such. If you happen to have leftover bread flour, you can use bread flour in place of AP flour (at a 1:1 ratio), for yeast doughs, like the ones mentioned under Bread Flour above.

Pastry Flour and Cake Flour

While these two flours aren’t exactly the same, they are both fine-textured soft flours with a low protein content (pastry flour clocks in at approximately 9 percent protein, while cake flour is even lower, with a protein content of about 7 to 8 percent). These flours have just enough protein to give structure to cakes and other tender-crumbed baked goods, while keeping texture deliciously airy and light.

In a pinch you can pretty easily and successfully substitute AP flour for cake flour and for pastry flour, by using this ratio: For every 1 cup cake or pastry flour called for in a recipe, measure 1 cup of AP flour, then remove 2 tablespoons (this will leave you with 7/8 cup of AP flour, also known as a scant cup, which you can alternatively measure by eye). Add 2 tablespoons cornstarch to your scant cup of AP flour and, poof!, you’re good to go.