There are many reasons to cook with flours made from plants other than wheat--other grains, seeds, tubers, and roots, including buckwheat, chick-peas, tapioca, and potatoes. For people who are allergic to gluten (the protein formed when wheat flour is made into batter or dough) or to wheat itself, these flours offer excellent alternatives. Nonwheat flours also have their own merits aside from their lack of gluten: Some are particularly high in protein, or in amino acids that wheat lacks. Some contain more dietary fiber than wheat, or offer phytochemicals that wheat does not. Some types of flour add unusual flavors, or are especially good at thickening liquid mixtures, such as sauces or soups (arrowroot and tapioca are in this category). There are some obstacles to deal with when nonwheat flours are used for baking. Because they produce little or no gluten when mixed with liquid, these flours need special treatment in order to form a workable dough or batter that will rise, hold its shape, and have a pleasing texture. If a wheat or gluten allergy is not the problem and the other flour is being used to boost flavor or nutrition, a suitable proportion of wheat flour can be added: As a starting point, use one 1 nonwheat for each 4 parts wheat flour. Amaranth flour: Milled from the seeds of the amaranth plant, this flour boasts a higher percentage of protein than most other grains, and has more fiber than wheat and rice. It is also higher in the amino acid lysine, which some food scientists believe makes it a more complete protein than flour made from other grains. Amaranth flour can be used in cookies, crackers, baking mixes, and cereals. However, it can be expensive and is not widely available. Arrowroot flour: The rootstalks of a tropical plant are the source of this flour, often used as a thickener for sauces and desserts; the finely powdered arrowroot turns completely clear when dissolved (giving gloss to sauces), and adds no starchy flavor. Because of its easy digestibility, it is also an used as an ingredient in cookies intended for infants and young children. Barley flour: This mild-flavored flour made from barley grain contains some gluten. Besan: (see chick-pea flour, below) Buckwheat flour: A common ingredient in pancake mixes, buckwheat flour is also used to make Japanese soba noodles. It is available in light, medium, and dark varieties (the dark flour boasts the strongest flavor), depending on the kind of buckwheat it is milled from. You can make your own buckwheat flour by processing whole white buckwheat groats in a blender or food processor. Chana:(see chick-pea flour, below) Chestnut flour: This tan flour is made from American chestnuts, the meaty, lowfat nuts that are often served as a vegetable. The flour is a little sweet and is traditionally used in Italian holiday desserts. Chick-pea flour (also called chana, gram flour or besan): This protein-rich flour is made from dried chick-peas (garbanzo beans). This flour is used commonly throughout India, and in parts of the Mediterranean as well, in pancakes, pizzas, dumplings, soups and stews. Make your own chick-pea flour by grinding lightly roasted dried chick-peas in a blender. Corn flour: This is made from whole cornmeal, ground to a floury consistency. You can make corn flour from cornmeal by processing it in a blender. Cornstarch: This silky ingredient is made from only the endosperm (starchy part) of the corn kernel. It is used to thicken sauces and to create baked goods with a particularly fine texture. Garfava flour: This flour is a blend of chick-pea flour and fava bean flour and can be used like chick-pea flour. Gluten-free flour mix: Some health-food stores carry this three-grain mixture of rice flour, potato starch, and tapioca flour. It can be substituted for 100% of the wheat flour in many recipes. Millet flour: This yellow flour is high in protein and easy to digest. It may make baked goods somewhat coarse-textured and dry. Substitute it for no more than one-fifth of the wheat flour in a recipe. Oat flour: Milled from either the entire oat kernel or the endosperm only, oat flour is frequently used in ready-to-eat breakfast cereals. You can make your own to use in baking by grinding rolled oats in a food processor or blender (1-1/4 cups rolled oats will yield 1 cup oat flour). Potato flour (potato starch): Steamed potatoes are dried and then ground to a powder to make this gluten-free flour, which is commonly used in baked goods for Passover (when wheat flour may not be used). Quinoa flour: Higher in fat than wheat flour, quinoa flour makes baked goods moister. You can make your own quinoa flour by processing whole quinoa in a blender; stop before the flour is too fine--it should be slightly coarse, like cornmeal. Rice flour, white: This very fine-textured flour is made from polished white rice. Rice flour, brown: Because it contains the bran, brown rice flour contains more fiber than white rice flour. Rye flour: In combination with wheat flour, rye flour, which contains some gluten, is most commonly used in breads. Light, medium, and dark varieties (with dark having the strongest flavor) are available. Light rye flour may be labeled "bolted," which means the flour has been sifted to remove the bran and germ. Dark rye flours are often "unbolted," and so contain a good deal more fiber. When adding rye flour to bread recipes, use less of the dark flour than you would of the light flour, or the flavor will be too dominant. Sorghum flour: Sorghum is a cereal grain that is little used for human consumption in the U.S., although it is a staple grain elsewhere in the world. Sorghum flour works well in breads when combined with bean flours. Soy flour: See Soy flour, Tapioca flour: Milled from the dried starch of the cassava root, this flour thickens when heated with water and is often used to give body to puddings, fruit pie fillings, and soups. It can also be used in baking. Triticale flour: A hybrid of wheat and rye, triticale is higher in protein than other non-wheat flours but still needs to be combined with a wheat flour to produce a satisfying texture. A close relative of wheat, it should not be eaten by those with wheat allergies. Water-chestnut flour (water-chestnut powder): This Asian ingredient is a fine, powdery starch that is used to thicken sauces (it can be substituted for cornstarch) and to coat foods before frying to give them a delicate, crisp coating.