Corn starch has many culinary uses, but it is most often used as a thickener for sauces, gravies and fruit pie fillings. Corn starch thickens very quickly and easily, and forms a clear sauce after cooking, rather than an opaque one. It has roughly twice the thickening power of flour, and while it is flavorless after cooking, it does need to be cooked for a short period to remove any starchy flavor from the starch, as well as to give the mixture it is used in a chance to thicken. Unlike flour, corn starch will clump up if added directly to hot liquids and must be mixed with a small amount of color liquid before being incorporated into something hot, such as a gravy or a pudding. It if is added to a cold mixture, it does not need to be prepared in any way before cooking and will dissolve as the mixture heats up. If cooked for an extended period of time, or whisked too vigorously, a mixture thickened with corn starch can break. Arrowroot and tapioca are both good substitutes for corn starch when it comes to thickening power.
http://www.chinafooding.com/Corn_starch
PR
