Baking with alternative flours versus unbleached flour is more about substituting for wheat than concern about whether the flour is bleached or not. Most baked goods rely on wheat flour because its proteins make such strong gluten, the substance that gives the goods structure. These days there's more emphasis on finding alternatives to wheat because increasing numbers of people are avoiding gluten for medical reasons. However, it's not always possible or even advisable to completely swap out unbleached wheat flour for non-wheat flour.
Choice Depends on Recipes
Nuts, legumes, grains other than wheat and some fruits and vegetables all can be ground into flour, though many of them behave differently than their wheat counterparts. Non-wheat flours, for instance, especially nut flours with lots of oil, tend to spoil much more quickly than wheat flour and must kept in airtight, refrigerated or frozen conditions. Choosing an alternative to wheat flour depends on what kind of baked good you're making, as many non-wheat flours have strong, distinctive tastes as well as varying abilities to perform the necessary chemical functions of baking.
Nut Flours Give Flavor
Nut flours such as almond and hazelnut can be substituted for a portion of wheat flour to add flavor and texture to baked goods. They also can be used as a dairy alternative in place of powdered milk. However, nut flours can't be substituted for wheat flour on a one-to-one ratio because they have no proteins to form gluten. For this reason, they work well in gluten-free desserts, particularly baked goods that don't need proteins for structure, like quick breads, pastry crust, cookies, muffins and pancakes or waffles. They also contain high amounts of oil, which makes the flour go rancid quickly. To use nut flour, swap it for one quarter of the wheat flour in a recipe.
Rice Flour Is Gluten-Free
Rice flours can serve as gluten-free substitutes for wheat, but can result in a grainy texture when used alone. Brown rice flour has more nutrients than white rice flour. Sweet rice flour is frequently used in sweets in place of wheat flour or cornstarch, both of which have gluten.
Yeast Breads Need Wheat
Yeast breads work best when no more than 15 to 25 percent of the wheat flour is substituted with alternative flour such as rye or potato. That's because bread needs wheat gluten to form a matrix that captures the carbon dioxide gas created by yeast to leaven the dough. One exception to this rule is oat flour, which has a higher protein content, 17 percent, compared to the average 12-percent protein content of most wheat flour. Oat flour can be substituted for as much as one-third of the wheat flour in bread.
Flour From Non-Wheat Grains
Flour made from other non-wheat sources such as millet is often found in Asian, Indian and North African cuisines, developed where the environment isn't conducive to growing large amounts of wheat. Actually a seed, millet has a nutty flavor and is the most digestible flour because of its fiber and phosphorus levels, which break down fats. Another alternative grain is spelt, which is actually a distant cousin of wheat with a tougher outer shell and a 15 to 21 percent protein value, higher than the average 12 percent protein in most wheat flours. Spelt can be substituted one-to-one for wheat, but the recipe's liquid should be cut by 25 percent because spelt holds moisture. Its gluten also is sensitive, so spelt dough shouldn't be over-kneaded to avoid breaking the matrix that holds carbon dioxide for rising. Breads made with spelt won't rise as high as wheat breads, but will have a similar consistency and taste.