Many other grains, such as amaranth, millet, teff, and barley, have limited used in the bakeshop, either as flour or as whole grains. Other starchy non-grain foods, such as potatoes and chestnuts, can be dried and ground into flour for special products. See, for example, the formula for Chestnut Bread. Cooked potato starch is sometimes added to yeast breads, because the starch is easily broken down by diastase enzymes into forms of sugar that yeast can use.