Corn starch, sometimes called corn flour, is the starch of corn. It is ground from the endosperm or white heart, of the corn kernel. Corn starch has a distinctive appearance and feel when mixed raw with liquids, such as water or milk. Because it tends to form lumps, Corn starch is mixed with a small amount of cold liquid to form a thin paste before being stirred into a hot mixture. It is usually included as an anti-caking agent in powdered sugar and confectioner’s sugar. Recipes calling for powdered sugar call for at least light cooking to remove the raw Corn starch taste.
Corn starch thickens with a satiny smoothness and glossy appearance. It adds no taste of its own to mask the flavor of foods. Recipes thickened with Corn starch have a brighter, more translucent appearance than those thickened with flour. Corn starch also blends more easily with cold liquids than flour because it doesn't absorb liquid until it's cooked.
Gluten is not present in Corn starch, which makes it an excellent substitute for flour in many recipes. Many people are sensitive to gluten and require gluten-free food preparation. In many baked goods like bread and cake, however, gluten plays an important structural role, and gluten-containing ingredients, like flour, are necessary. Check the recipe to see if Corn starch can be used as a substitute for flour, before preparing.
Corn starch is commonly used as a thickening agent for puddings, sauces, and soups. Mixing it with a granular solid such as granulated sugar will also help it disperse into a liquid. Sauces thickened with Corn starch tend to be clear, rather than opaque, as with flour-based sauces. However, the sauces will thin if cooked too long or stirred too vigorously. Corn starch is used in combination with flour in many European cake and cookie recipes because it produces a finer-textured, more compact cake or cookie than flour alone.
Corn starch is used as a thickener for gravies, sauces and glazes, soups, stews and casseroles. It also thickens pies and is an essential ingredient in Corn starch puddings and cake fillings. In cakes, cookies and pastries, Corn starch is often mixed with flour to produce more tender baked goods. Additionally, it is used to coat foods before frying, and as an ingredient in batters. Most of the packaged pudding mixes supermarkets and grocery stores include Corn starch. Corn starch puddings can be made at home, using a double boiler. The most basic pudding uses only milk, sugar, Corn starch, and a flavoring agent.
Corn starch has the same "thickening power" as arrowroot, potato starch and tapioca, and you should substitute the same amount. Corn starch has twice the thickening power of flour, so it is necessary to use only half as much. The following conversion chart can be used to calculate the correct amount of Corn starch to use.