Our beloved kitchen product – the aluminum foil – has two completely different faces! One side of the sheets shines as if it is the moonlight itself, the other not so much. This gives rise to two questions:

  • Why are there two sides that look exactly the opposite of each other?
  • Which side should you use in the kitchen?


People will give you all sorts of theories to explain why this is so. One popular one that has been making its rounds is that the reason household aluminum foil has a dull and a shiny side is scientific. The shiny side will reflect the heat on to whatever you have in the oven. This is also supported by the scientific principle of light and heat reflection by shiny surfaces.

If that were true, turning on your kitchen grill and placing your hand on its side would not prove that the dull side reflects heat equally well. Hold the piece of aluminum foil to reflect the heat from the heating element in the grill to your hand. Repeat the experiment with both sides of the foil and you will have your answer: both sides reflect heat equally.

The real reason behind this is nothing more than the way aluminum foil is produced. To roll the foil down to the cooking-appropriate thickness (approximately 0.01 mm), a rolling mill is used. This mill presses down two coils simultaneously by a process called ‘doubling’. The side that encounters the rolling mill is the external side while the inner surface stays safely tucked in. That is why the external side is shiny and the internal is matt for both the coils.


With the short experiment above, it is plain for anyone to see that while some cooks might prefer to use one side or the other during cooking, both sides reflect heat equally. In another experiment, two baking pans were used. One had bacon that was covered with the foil, shiny side up while the other bacon bundle was covered with foil shiny side down. To the center of both meats was added a probe thermometer. On baking the piece of bacon, it was discovered that both took the same amount of time to reach the same temperature. When the foil sheets were cracked open, both revealed crisp bacon in all its golden glory!

Final verdict for all foil-lovers: use the side you want!

Drop by to tell us which side of foil you prefer to use and why! Symintec, we bridge the gap between you and success with quality aluminum!