Using aluminium foil as an oven liner is a fairly common kitchen practice, and one frequently recommended by cookbooks and consumer websites. The practice minimises oven clean up, avoiding the use of toxic oven cleaning chemicals. Yet, it is a practice many oven manufacturers discourage and is not recommended by one major manufacturer of aluminium foil.
Instead of placing the aluminium foil on the bottom of the oven, the manufacturer of ReynoldsWrap recommends place it on the rack below the one on which the cooking food is sitting to avoid heat damage to the oven. Use a sheet of foil slightly larger than whatever you are cooking or baking, so that the foil will catch any spill over. Don't use a sheet much larger than the cooking pan, as you don't want a large sheet of foil inhibiting the heat circulation.
While many sources, including Oregon's Metro Regional Government website and Hawaii's Pollution Prevention Information report recommends using aluminium foil as an oven liner, oven manufacturers typically warn against this practice. Using aluminium foil as an oven liner can result in a fire or electric shock, according to Bosch and Kenmore. Before lining the bottom of your oven, review your owner's manual.
Many consumers regularly cover their grills with aluminium foil, with the intention of simplifying clean up. Instead of scrubbing off stubborn cooked on food, the cook removes the foil and throws it away. Yet, a number of oven manufacturers, including Bosch and Kenmore, warn against covering grill inserts with aluminium foil, stating that grease or fat on the foil could ignite.
While the aluminium foil will help keep the bottom of your oven clean, don't use it to line the bottom of your microwave oven. Wrinkled foil can cause sparking in the microwave. In some instances, it is safe to use foil in the microwave to cover food, yet always refer to your microwave oven's owner's manual before using foil in the appliance.
If you do choose to line your oven with aluminium foil, use heavy-duty foil. Don't place the foil next to a heating element, as it could ignite. Remove any dirty foil lining before heating the oven. Food left on the foil and allowed to reheat could ignite and cause the foil to catch fire. While a foil aluminium liner will minimise clean up, if left on the bottom of the oven to continually collect spills, it not only poses a fire hazard, it makes a sticky mess.