Have You Been Using Aluminum Foil Wrong? Here's The Truth About Its Shiny & Dull Sides

When you unroll that length of foil to wrap your filet or cover your casserole before sticking it in the oven, do you ever ponder which side should be facing up? There is a shiny side and a dull side to foil, and you may have grown up learning that these sides have different purposes. Common myths still circulating around social media are that the shiny side of foil reflects heat better and should be facing food you want to keep warm, and facing away from food you want to keep cool. But the truth is, it doesn't really matter which side is up or down, and effects on temperature are negligible at best.

Aluminum foil, also called tin foil, is made by melting together aluminum, iron, and silicon and sending this mix through a heavy-duty roller to create those handy, thin sheets that can be used in a number of genius household hacks. The shiny and dull sides come from this manufacturing process. The final rolling stage creates a polished side of foil that was touching the rollers, and a matte side that wasn't. The material on both sides is made of the same stuff and operates the same way. The popular myth that the two sides handle heat differently isn't actually true.

Some brands of foil have a non-stick version where the side does indeed matter. The dull side will have the non-stick coating applied, and that's the side you want facing the food or surface to which you don't want any sticking. Using non-stick foil can make baking cleanup a breeze and works well when wrapping foods up for freezing. But with regular foil, either side works the same.

Whichever side you choose, there are a few places you don't want to use foil at all. Don't line your oven with foil, or you risk interrupting air and heat flow, and you should never microwave it as it can spark and cause a fire. When it comes to cooking and food storage, keep in mind that foil isn't airtight when using it to wrap leftovers, and baking cookies on foil can burn their bottoms. For all those other nifty uses around the home, like scrubbing away hard water stains or sharpening your scissors, shiny or dull won't make a bit of difference.