Does it matter which side of aluminum foil goes where?

Aluminum foil gets a workout in our house, from covering and lining pans to zhushing up cake boards. For the cake boards, it is obvious that the shiny goes on the outside, but when you are using it in the oven or on the grill, does it matter which side goes where? The short answer is, not really.

You might think there is a difference in the heat reflection from the shiny side to the dull side, but there is not any meaningful distinction. So then why is one side shiny? The answer lies in the milling process, during which heat and tension are applied to stretch and shape the foil. Two layers of foil are pressed together as the metal goes through the mill to prevent the delicate metal from tearing. The side that is exposed to the roller becomes shiny, while the side that is in contact with the other aluminum stays dull.

There is one product where the sides do matter: nonstick aluminum foil, which is only nonstick on one side. Most nonstick foil is clearly labeled as to which is the right side to be in contact with the food, so it should not be difficult to use the correct side. While foil is generally safe to use for cooking, some studies have found that small amounts of aluminum can leach into the food, especially meats and acidic items, so if that’s a concern you may want to opt for a different material.