 Food to be grilled is cooked on a grill (an open wire grid such as a gridiron with a heat source above or below), using a cast iron/frying pan, or a grill pan (similar to a frying pan, but with raised ridges to mimic the wires of an open grill).Heat transfer to the food when using a grill is primarily through thermal radiation.Heat transfer when using a grill pan or griddle is by direct conduction.