In short, science says it makes no difference at all, and there is no correct or incorrect way to use aluminium foil, as confirmed by Robert L. Wolke in What Einstein Told His Cook and America’s Test Kitchen. You can place either side in either direction whether cooking or freezing food with aluminium foil.
Just so, can you put foil directly on oven rack?
“To avoid possible heat damage to your oven, we do not recommend using aluminum foil to line the bottom of your oven. Rather, we recommend that you place a sheet of heavy duty aluminum foil on the oven rack beneath the pie or casserole you are baking. … The foil will catch any drips before they reach the oven bottom.”
Keeping this in consideration, which side of the aluminum foil is the non-stick side?
The shiny side is face-up on the roll, and the dull side is on its underside. In other words, feel free to use whatever side makes you happy. But, if you are using non-stick foil, there is a difference between the two sides because the non-stick coating is only applied to one side.
Why does aluminum foil have a shiny side and a dull side?
03/5How aluminum foil gets two different sides
The side of the foil that is in contact with another layer ends up becoming the dull side, while the side which is milled without being in contact with another layer ends up becoming the shiny side. Hence, the origin of two dissimilar sides.