What is the reason for using aluminium foil to wrap the food items?

[Garvi]

aluminium is a good conductor of heat, but still it is used so that food remains warm. what is the reason behind it?

 

[sophiecentaur]

It is a good conductor but a very poor radiator and absorber (the two go together) - because it is shiny. The inner surface, where not actually in contact, will not absorb radiated heat well and the outer surface will not radiate heat well. Hence the food will not lose much heat.

It is also cheap to produce in suitable sheet form.

 

[Manis]

Aluminium foil has smooth shiny surface. Due to which it reflects back the heat raditations emitted by the food stuffs upon them. Hence food remainr warm for longer time.

Also i think in this case, reflection through its surface is very higher than conductance.

 

[Manis]

Aluminium foil has smooth shiny surface. Due to which it reflects back the heat raditations emitted by the food stuffs upon them. Hence food remains warm for longer time.

Also i think in this case, reflection through its surface is very higher than conductance.

 

[turbo]

I use aluminum foil as a matter of convenience. When roasting poultry or poultry parts, I cover the pan with foil to keep the juices contained. The meats produce enough steam to cook themselves. Then, when the meat is cooked through, I pull off the foil "tent" and set it aside as the meats go back in the oven to brown. After serving the food, leftovers can be wrapped in the foil for later use. If the extra meat is to be frozen, I usually use a bit of poly-wrap, and then seal that in the left-over foil. When the aluminum foil has served several purposes, it ends up in the metal recycle bin.

 

[rude man]

Probably because Reynolds and Alcoa use a lot of TV advertising.

More seriously: it is resistant to any amount of heat, seals well and does not puncture easily. I think the thermal properties are a lesser factor in explaining its ubiquitous use.

 

[sophiecentaur]

Aluminium foil has smooth shiny surface. Due to which it reflects back the heat raditations emitted by the food stuffs upon them. Hence food remainr warm for longer time.

Also i think in this case, reflection through its surface is very higher than conductance.

In common with millions of other people, you are ignoring the low emissivity of the outside surface, which is just as important as the "reflecting the heat back' on the inside. If you had a matt black outer surface, the food would cool much faster.

But Rude Man is absolutely correct in pointing out its other advantages over other food covering material. Once the oxide layer has formed on the surface of aluminium, it is pretty well non reactive to foodstuff. However, hot juices from fruit etc. can visibly etch it and that means some Al can get into your system. Remember the hassle about Aluminium cookware and Alzimer's a few years ago? (I have forgotten it already.)