Foil: why is one side shiny and the other matte – the answer is simple
Foil is often used in cooking, construction, medicine and even for decorative purposes. However, many people wonder: why is one side of it shiny and the other matte? Everyone understands that this is not a coincidence or a design idea, but only a few know the correct answer. Why does foil actually have such different sides, experts told, informs Ukr.Media.
How and what is foil made of?
Foil is made from aluminum by rolling. This process is long and involves several stages. First, the aluminum is melted, poured into special molds, and blanks are obtained. Then they pass through rolling mills and become thinner.
To achieve the minimum thickness, the sheets are passed through the rollers several times.
It is at the last stage that the difference in the texture of the sides appears. The thing is that thin foil cannot be rolled alone – it is too fragile and can tear. Therefore, it is folded into two layers and rolled simultaneously.
During the rolling process, the sides pressed against the rollers become smooth and shiny as the metal rollers polish the surface. The sides that touch each other inside the folded sheet are not treated in this way and therefore remain matte.
Is there a difference between the matte and glossy sides of foil?
There is a common myth that the shiny side reflects heat, while the matte side absorbs it better, so foil should be used on a specific side when cooking.
Many housewives and even chefs advise wrapping meat or chicken for baking so that the glossy side is facing inward. It is believed that this way you can retain more heat. In fact, the difference in thermal conductivity between the sides is so insignificant that it practically does not affect the cooking process.
But when storing food, the shiny side does indeed reflect heat and light much better. Therefore, it is better to pack food with the shiny side facing out.
The same effect is used in construction: during the thermal insulation of buildings, aluminum foil is used to reflect heat, and therefore the shiny side is also directed outwards.
But in interior design there is no general rule, where the use of the matte or glossy side of the foil depends solely on the author's intention.
The same applies to the production of medicines: foil packaging does not affect the pills or capsules in any way, so it makes no difference which way you unfold the aluminum foil.
Джерело: Source
