If you’ve used aluminum foil, you might have noticed one side is shiny while the other is dull.

This has sparked debates in kitchens worldwide—does it matter which side you use? The answer may surprise you.

How Is Aluminum Foil Made?

Foil starts as a thick slab of aluminum that is rolled into thin sheets. At the final stage, manufacturers roll two sheets together to prevent tearing. The side touching the rollers becomes shiny, while the side pressed between the sheets stays dull. It’s a mechanical result—no coatings, no treatments, just physics.

Does the Shiny Side Cook Better?

A common myth is that the shiny side reflects heat better. However, the difference in reflectivity is minimal and has no real impact on cooking. Whether wrapping food for baking or covering a dish, both sides perform the same.

Is One Side Safer for Food?

Both sides are food-safe. However, foil shouldn’t contact acidic foods like tomato sauce for long periods, as acid can break it down slightly.

When Does the Side Matter?

The only time it matters is with non-stick foil, where the dull side is coated. Always follow packaging instructions for proper use.