Should You Use Aluminum Foil With The Shiny Side Up Or Down?

It’s time to dig into one of the kitchen’s biggest mysteries.

aluminum foil
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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.

Should You Use Aluminum Foil With the Shiny Side Up or Down?

So, now that you know the reason behind the different appearances of the two sides, you're probably wondering if you should use aluminum foil with the shiny side up or down. Quite simply, it doesn't matter.

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.

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