Unshaped large chunks, usually about 1 to 2 centimeters (⅜ to ¾ inch) in size. These pieces are used as the aromatic elements to flavor the final product and are almost always strained out of the sauce at the end of cooking; therefore, a perfect symmetrical shape is not required. Mirepoix may be cut without first shaping the vegetable by any of the traditional cutting methods, but it is important that all pieces be of uniform size to ensure even cooking. This term is often applied to a mixture of equal parts onion and carrot; 50 percent onion, 25 percent carrot, and 25 percent celery; or equal parts onion, carrot, and celery (depending on the specific recipe) that is used to flavor stocks and sauces. Onions are always a component of a mirepoix, though carrots and celery may not always be used.