This is just not so. The surface of the aluminum layer that is in contact with atmosphere oxidizes and turns into aluminum oxide — hence the matte side. Foil can be used to make some kind of molds, in which it is very convenient to bake cupcakes, pies or any other dough product you want. The performance of the foil is the same, whichever side you use. The other side has a matte finish. In fact, some cooks wrap potatoes in aluminum foil dull side facing out during baking with the belief that the shiny side reflects heat toward the potato, cooking it faster. Trust me, it wasn’t pretty. The official word from the Reynolds aluminum people is as follows: "It makes little difference which side of the Reynolds Wrap aluminum foil you use--both sides do the same fine job of cooking, freezing, and storing food. Non-stick foil is a good choice when baking dishes that can get sticky, like macaroni and cheese. With regular aluminum foil, it doesn’t matter which side of aluminum foil is used. Fire in the Foil When you wrap a potato in aluminum foil, the foil acts as a heat conductor. When it comes to nonstick foil, the dull side (nonstick side) should be the side that actually touches food. The side of each sheet that comes in contact with the polished steel rollers comes out shiny. When baking potatoes, the aluminum foil performs the same -- shiny side facing in or out. Before aluminum became readily available during the late 19th century, a lesser thin foil made of tin was used commercially (tin foil). That latter one Mr. Fantabulous and I got into a huge lengthy discussion about it. And what side of aluminum foil should we be cooking on – shiny or dull? I mean we nerded out big time and even now we are STILL debating this. Putting an age old debate to bed. Apr 17, 2020 2:38pm. A very important investigation. Do I use the shiny side or dull side of aluminium foil when baking? The exception to this rule is the non-stick type of aluminum foil. However, the reflective and insulative properties of this material make it useful far beyond the kitchen. In that case, we should use the shiny side, since aluminum oxide is not that healthy. How to Use Aluminum Foil. In the oven, the foil in the form of baking molds should be placed with the matte side outwards so that the dough does not stick to it. StockImages_AT via Getty Images The shiny side is face-up on the roll, and the dull side is on its underside. Aluminum foil is actually made of two layers: one of aluminum, another that is coating. The other side has a matte finish. We’re talking about heat refraction, types of heat used and so forth. Aluminum foil is commonly used for baking, cooking, and packaging food. Baking Cans. Fun fact: tin foil and aluminum foil, while often used interchangeably, are quite different.