Cooking results are significantly affected by the position of the wire shelf as this determines how close the food is to the heating elements. Certain food dishes benefit from varying the shelf position. We've got some tips for determining the best position.
If a recipe does not specify where to place your food in the oven, keep the wire shelf adjusted to the middle position as this works best for most cooking and baking situations. The middle shelf allows hot air to circulate evenly around the food, resulting in even cooking; this is great for pizzas and flatbreads.
The top shelf is ideal for using the broiler, and can be used for pans with about 1"" or less depth. The bottom shelf yields close proximity to the heat source, making it perfect for cakes that require a short exposure to intense temperatures.
Also note, when using metal foil to cover dishes, it is recommended that the wire shelf be in the middle or bottom position.