Although risotto is sometimes made with water, it is normally cooked in stock. A light-flavored stock is preferable because the flavor will concentrate as the broth reduces during cooking. Vegetable, poultry, fish, and meat stocks are used, depending on the risotto. Veal stock is never used. While one can approximate the quantity of liquid necessary for a given weight of rice, the exact amount varies depending on a number of factors, including variety and age of rice, size and depth of cooking vessel, and rate of cooking. Liquid should be brought to a simmer separately so it is always added to the rice hot.