I would imagine that traditional whole wheat flour is the most common whole grain used in baking today. But I have recently become aware of several variations of whole wheat flour, and other grains that are very healthy and taste great in all kinds of baking. Here's a little of what I have found out:
Traditional Whole Wheat Flour- is the all-purpose flour of the whole grain world. It can be used for anything from cookies to sandwich breads to pizza crusts. This variety may be a bit bold or "heavy" for some tasks, where white whole wheat flour might be better suited.
White Whole Wheat Flour- is not a mix of white flour and whole wheat flour, as I thought at first. It is flour made from white wheat, as opposed to red wheat that traditional whole wheat flour is made from. This flour is lighter in color and texture than traditional whole wheat flour. The brand I use is King Arthur Flour Unbleached White Whole Wheat Flour.
Whole Wheat Pastry Flour - is made from soft whole wheat, and has a finer texture than traditional or white whole wheat flours, which are both milled from hard wheat berries. As its name implies, whole wheat pastry flour is great for...pastries (of course)...and muffins, biscuits, pancakes, and scones - anything where you want a more tender crumb and less chewy texture.
Oats and Oat Flour - Oats work very well in yeast breads, are excellent in cookies, scones, and streusels, and on their own as oatmeal. Oat flour is too dense to work in foam cakes like genoise or jelly rolls, but is fine in stir-together cakes and many other desserts.
Whole Cornmeal -works best with quick breads, flat breads, and tortillas. It combines well with rye and whole wheat, making excellent breads and cakes.
Barley Flour -Not much baking is done with barley alone; it is almost always paired with wheat flour in baked goods. It works well in goods not requiring a lot of structure -- cookies, sparingly in muffins, quickbreads, cakes, piecrusts, etc. -- and very sparingly in yeast breads that you want to rise quite a bit.
Rye Flour - can have a "gummy" quality that doesn't disappear by baking it. Rye can be used in crackers, waffles, and biscuits fairly well. Rye bread is challenging to make, but can be done successfully -- though it may take several tries to get a rye bread you like!
Spelt Flour - The key to working with spelt flour is letting it rest -- to soak in liquid, let it out, and re-absorb it again. With this rest (overnight in the fridge is sometimes necessary), spelt is excellent in cookies, muffins, cakes and yeast breads - with a little babying involved.
Buckwheat - has a strong flavor and no gluten in it, making it necessary to combine with another flour for baking. It is not suitable for cakes or quickbreads, but much better in biscuits and pancakes.
Rice and Rice Flour - is also gluten-free, so combining it with other whole grain flours is often helpful (unless you are on a gluten-free diet!) Baked goods made with rice flour do tend to be crumbly, but rice flour can be good in cookies and crackers.
Amaranth - another gluten-free grain, made of tiny seeds of a leafy plant. It is usually paired with other flours to help it out. It has a high oil content, and can go rancid if not used fairly quickly.
Teff -another gluten-free grain, long used as a staple grain in Ethiopia. In the US, it is generally used as an additive to other flours in a recipe, and not on its own.
Triticale - does have gluten, but is more delicate and decomposes faster. It can be used in breads and other baked goods.
Quinoa - another "seed-grain" that is gluten-free; but must be rinsed thoroughly before cooking (the seeds are covered in a bitter, soapy-tasting substance that repels birds and other potential pests). The flour can be used for gluten-free baking.
Millet - gluten-free and usually used in combination with other flours in baking, though it does give baked goods a soft, crumbly texture. It is usually prepared whole in porridge or pilaf, but sometimes in flatbreads.
Kamut - is a type of wheat, related to the durum wheat mentioned above, and can be used almost interchangeably for whole wheat flour. However, kamut has not yet caught on as a crop or as an ingredient, and can be considerably hard to find.
Source: King Arthur Flour Whole Grain Baking, 2006.
Well, since tomorrow is a holiday and I have neither work nor school, I expect to be back on here with another recipe or two and more pictures of my adventures in baking!