Seitan can be prepared from scratch using whole-wheat flour. The flour is mixed with enough water to make into a dough that is then kneaded in water and rinsed to remove the starch and the bran. The protein, or gluten, remains and is then simmered in a broth flavored with soy sauce to become seitan. The longer the gluten simmers, the firmer it becomes. Seitan can then be sliced for sautés or stir-fries, diced into stews, soups, or casseroles, or formed into roasts. People who are allergic to wheat or wheat gluten should avoid seitan.