Why is foil shiny on one side

But one of the cheapest kitchen accessories all cooks agree on? Aluminum foil. We'd be remiss if we didn't acknowledge it as one of the hardest working tools in our arsenal. And if you use aluminum foil as often as we do, you have probably noticed that one side of the foil is shinier than the other. Maybe you see the shiny side as the "right" or "top" one and always have it facing up.

Start your FREE trial. Fine Cooking. Sign Up Login. Save to Recipe Box. Add Private Note. Saved Add to List Add to List. Add Recipe Note. Most Popular. Classic Tomato Soup Recipe. In reality, in the long length of time it takes to bake a potato, either side will work basically the same. 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. Rather than which side is out, a bigger difference may be made by how tightly the potato is wrapped.

Any air trapped in the aluminum foil pouch and surrounding the potato may act as an insulating barrier, slowing the transfer of heat. So, wrap your potatoes tightly before baking. 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.

The manufacture of aluminum foil is similar to making pasta at home. 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.

Lubricants are added to facilitate the operation. At each successive pass through the rollers, the thickness is reduced.

The process is repeated until foil thickness is reached, and the large flat sheet is then split into the desired widths. This may seem simple enough, but the actual process can be tricky. For example, as the aluminum is rolled out, it heats up. If it heats up too much, it can stick to the rollers, so the roller pressure must be carefully controlled. Once the sheet of aluminum is 5mm thick, it must be rolled again in the cold-rolling stage. First, the sheet is spooled into a roll and then it is fed into the cold-rolling mill for the final stage of milling.

It is at this point that the shiny and dull sides of the aluminum are created. The kitchen can be a confusing place for most novices. Things like how to chop vegetables or how to properly heat food can intimidate those who are not familiar with kitchen regulations. Aluminium foil is widely used as a tool in the kitchen, but little do we wonder why one side is dull, and the other shiny.

Today we will find out why. Since aluminium foil comprises of two sides, have we been using it wrong? Does the shiny side reflect more heat while the dull side is a better conductor? The reason why aluminium foil has two different sides is because of a manufacturing process called milling. The process of milling is responsible for two differently appearing sides. In the process, heat and tension is applied to stretch the foil to the desired thickness, and to do so, two layers are milled in contact with each other to prevent foil breakage during the process.

The side of the foil that is in contact with another layer ends up becoming the dull side, while the side which is milled without being in contact with another layer ends up becoming the shiny side. Hence, the origin of two dissimilar sides. In this foil, the non-stick coating is only applied to one side, which is dull side, so using the shiny side would be futile. Aluminium foil has no one side that is superior to the other, and either can be used for the same purpose.

The reason the two sides are different is because of the manufacturing process called tilling. However, when it comes to non-stick foil, there is a designated side, which is the dull side, as the non-stick coating is only applied to that side. A weekly guide to the biggest developments in health, medicine and wellbeing delivered to your inbox.

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