According to Reynolds, this is a common question that they receive on a regular basis. The sides of the aluminum that come in contact with the steel rollers become more polished and shiny, and the sides of the aluminum that come in contact with itself become duller. There are three basic ways heat can be transferred: conduction, convection, and radiation. Chef Tom Kerridge showed watchers how to use tin foil on his BBC Two show Fresh Start and sent Twitter users into meltdown after explaining that you should put the shiny side face down… When the sheets of aluminum are rolled out, the side that comes in contact with the rollers come out shiny.. The reason happens to be a simple one: the foil is milled in layers. The hot air of the oven transfers heat to the food being cooked. You really do learn something every single day, don’t you? When it comes time to solve all of the great mysteries that life keeps presenting to us, we have got you covered. When wrapping potatoes in aluminum foil for baking, you probably tend to place the dull side out. However, their explanations make little sense. You get to decide which side of the foil should be facing outwards and the choice is always going to be a matter of personal taste. The other 1.5 percent is made up of silicon and iron to give the packaging material its strength. Yes, the shiny side is more reflective but reflective of what? Not very informative! Since I already mentioned the manufacture of foil through the explanations given above, I may as well write a bit more about how foil is made. There’s actually a reason as to why this is and Reynolds Kitchens is here to provide answers. The other 1.5 percent is made up of silicon and iron to give the packaging material its strength. https://www.womansday.com/.../a60228/right-side-of-aluminum-foil Should The Shiny Side Of Aluminum Foil Be Up Or Down When Cooking? Don’t be confused by “convection ovens.” All ovens use convection, convection ovens just use a fan to make the convection more efficient. Both sources provide the following, similar explanation (paraphrased): Aluminum foil has a shiny side and a dull side. At each successive pass through the rollers, the thickness is reduced. Blackened Fish Tacos with Creamy Coleslaw. This is because the shiny side is more reflective and so will reflect more of the radiant heat than the duller side. We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites. The foil will be heated through convection and this energy will be transferred to the potato, and as the moisture in the potato heats up, the potato is cooked through steam. All Rights Reserved. Only a little of the heat transfer in an oven is through infrared radiation, which is invisible light rays. Maybe you see the shiny side as the "right" or "top" one and always have it facing up. Did you know that plastic pen caps come with holes so that you can remain safe if you happened to swallow one by accident? Ads are what helps us bring you premium content – thank you! Since aluminum foil has a shiny side and a dull side, many cooking resources say that when cooking foods wrapped or covered with aluminum foil, the shiny side should be down, facing the food, and the dull side up. The truth is that it makes no difference at all. Please contact for permissions. For example, Robert L. Wolke in What Einstein Told His Cook and America’s Test Kitchen say that it makes no difference at all in cooking. This article contains one or more Amazon affiliate links. How to Line a Baking Pan with Aluminum Foil - David Lebovitz Since aluminum foil has a shiny side and a dull side, many cooking resources say that when cooking foods wrapped or covered with aluminum foil, the shiny side should be down, facing the food, and the dull side up. Fun fact: tin foil and aluminum foil, while often used interchangeably, are quite different. Aluminum foil is made from 98.5 percent aluminum. There is no difference. Now that the terms have been adequately clarified, here's the truth: it makes no difference which side is up or down! We’d like to send a big “thank you” to the good folks at Reynolds Kitchens for providing us with these insights. While some small amount of additional energy will be reflected by the shiny side, the difference is so small that it will make no practical difference in cooking. If these layers were not brought into contact with each other during the production process, the foil would break. People always ask, "Which side of the foil should it face up or down?" The process is repeated until foil thickness is reached, and the large flat sheet is then split into the desired widths. Any air trapped in the aluminum foil pouch and surrounding the potato may act as an insulating barrier, slowing the transfer of heat. It simply reiterates, with a bit more explanation, that foil does, in fact, have a shiny side and a dull side. There is no difference in how they cook. So what’s the truth? All content © 2019 by Eric Troy and CulinaryLore. The shiny side is face-up on the roll, and the dull side is on its underside. Chris Winters. A large block of almost pure aluminum is rolled through giant steel rollers, several times, reducing the thickness of the aluminum block and spreading it out to make it longer. One side is shiny and the other side is dull. It is at this point that the shiny and dull sides of the aluminum are created. Have you ever thought about why the two sides have different finishes, though? You may have suspected that there is a hidden feature to your aluminum foil as well. We know that this is the answer you have come for. Shiny surfaces reflect waves more than dull surfaces. Many people believe that it matters which side is used up or down. Once the sheet of aluminum is 5mm thick, it must be rolled again in the cold-rolling stage. The explanation does not support the claim. This means that the heated coils, sides, and racks in your oven are emitting infrared energy. Many of the objects that we use on a regular basis have hidden features. There’s actually a reason as to why foil has a shiny side and Reynolds Kitchens is here to provide answers. nce aluminum foil has a shiny side and a dull side, many cooking resources say that when cooking foods wrapped or covered with aluminum foil, the shiny side should be down, facing the food, and the dull side up. The truth is that the shiny side of aluminum foil is only a little bit shinier than the dull side. The foil is opaque, no matter which side is up. This is because the shiny side is more reflective and so will reflect more of the radiant heat than the duller side. So which side of the foil do we need to be using? Honest! So, the shiny surface of the foil should reflect more radiation than the dull surface, which will be better able to trap incoming waves rather than reflect them back. But it should not affect convection, the major source of heat transfer. You can place either side in either direction whether cooking or freezing food with aluminum foil. I tend to have a habit to have the dull side facing up. The reason the two sides look different is due to the manufacturing process. Consider a baked potato. To say that there is no effect whatsoever is inaccurate and it probably still is a little more efficient to cook with the dull side out.