All-purpose flour is the most suited and used flour for baking purposes. The gluten content in it makes it perfect to get the desired result, be it taste-wise, texture-wise or appearance-wise. That being said, people are on the look out for flour substitutions for a variety of reasons. Be it for health reasons, allergies, unavailability, etc.
Flour substitution is not as easy as simply using any other flour instead of all-purpose flour in a given recipe. Even though it gives a good taste, texture and look, the nutritional value is almost nil except for the vitamins and minerals which are mandatorily added these days to enrich it. Even then it is just plain starch without any fiber content, which is one of the essential nutrients for our bodies.
So many bakers are moving towards incorporating all kinds of whole grain flours while baking. Whole wheat flour, whole wheat pastry flour, oat flour, barley flour, quinoa flour, millet flour, etc just to name a few. But the only problem is these flours usually don't work out exactly like all-purpose flour because it's whole grain and the difference in the gluten quantity in such flours and also because of the high fiber content.
Treats baked using whole grain flours generally tend to be on the heavier side, don't rise as much as it's white counterpart and the taste might also need some time to get used to. But once you start baking with whole grain flours regularly you will crave for that more and more and wouldn't even go back to baking with regular white flour. The recipe might need some minor changes to be incorporated to get better results, like increasing the baking powder/baking soda a little bit, not over mixing the batter thereby over working the gluten which will end up in hard, dense and heavy baked treat, etc.
To start with one might try substituting 1/3rd or 1/2 a portion of all-purpose flour with the whole grain flour of your choice. See how it works out and then from there move on to increase the quantity of the whole grain flour. Pretty soon you will end up baking with it 100%. That's where I'm now. Whole wheat pastry flour especially is a boon for people like me; those who want to bake healthy. This works in all types of baked treats, be it cakes, cupcakes, cookies, muffins, scones etc. Because it is milled from soft whole wheat the gluten content is not as high as regular whole wheat flour making it perfect for all treats.
Other whole grain flours don't work exactly like whole wheat pastry flour so may not be suitable for all types of recipes. Quinoa flour, oat flour, barley flour etc maybe partly used in a recipe in combination with either all-purpose flour or whole-wheat pastry flour. These flours might especially be suited for cookies, scones and sometimes in muffins too.
Some other examples of flour substitution:
Flour Substitution Chart
For 1 cup sifted all purpose white flour, substitute:
- 1/4 cup soy flour plus 3/4 cup white flour
- 1/3 cup wheat germ plus 2/3 cup white flour
- 1/3 cup whole wheat flour plus 2/3 cup white flour
- 3/4 cup coarse cornmeal
- 3/4 cup rice flour
- 1 cup rolled oats
- 1.5 cups oat flour
Note that these substitutions may require additional leavening, so add 2.5 teaspoons baking powder per cup of flour to compensate. These alternatives to white flour will result in a heavier yeast bread product.
Gluten-free baking is yet another ball game altogether. At least it is not as difficult as it was even a decade ago. Thanks to the wide spread awareness of the Celiac disease in specific and gluten intolerance in general. These days it's not at all difficult to locate gluten-free flours. Some of those are amaranth flour, coconut flour, almond flour etc. But the drawback is all-purpose flour can't be simply replaced by these flours. Recipes have to be tweaked to get decent results. Even ready to use gluten free mix is easily available these days. Gluten-free baking along with egg-free is when it gets really complicated.