Aluminum Foil is an indispensable item in nearly every household. It's versatile: You can use it for everything from foil packet recipes to cleaning your grill. The handy product comes equipped with a bit of a mystery, too. One side of a sheet of aluminum foil is shiny, and the other side is dull and flat. You won't find any information about the reason for the difference if you check the rectangular box it's sold in either. So what gives?
Is it best to position aluminum foil with the shiny side up or down before you put that casserole in the oven? Before you tear off another sheet, here's what you need to know.
Why Is Aluminum Foil Shiny on One Side?
When you pull a sheet of aluminum foil off the roll, there's a notable difference between the two sides. One is so shiny that you can practically use it as a mirror. The other, well, it's still silver but not nearly as sparkly. It turns out there's a good reason.
According to Reynolds Wrap, the difference is a byproduct of the manufacturing process. You see, aluminum foil is milled in different layers. Heat and tension are applied to stretch the foil until it's thin enough to become the familiar sheets you buy in stores and use at home.
The factory manufactures two sheets of metal simultaneously to ensure the sheets are strong enough to withstand breakage. The side where the foil comes into contact with another layer of foil appears dull, while the other side, which hasn't made contact with another sheet, appears shiny. In other words, the two sides look different, but when it comes down to it, they're both made of the same stuff.
Does the Shiny Side of Aluminum Foil Reflect More Heat?
Aluminum foil reflects heat from both its dull and shiny sides equally. While aluminum foil has a dull and shiny side, there is no difference in how either side reflects heat.
Should You Use Aluminum Foil with the Shiny Side Up or Down?
Quite simply, it doesn't matter what side of aluminum folk you use. Either is acceptable. Since the exact same material makes up both sides, they will perform precisely the same way. The only difference is aesthetic. So feel free to work both ways. In the end, your food will cook the same. Mystery solved.