Why do so many people use aluminum foil wrap to keep food warm? It does not work because aluminum foil is a conductor, not an insulator. Here are some experiments you may try to see for yourself.
The next time you serve hot dogs, wrap one cooked hot dog in foil and another in a paper napkin.
Wait about 15 minutes and unwrap them. The one in the foil will be cold because the foil conducted the heat away. I had the same experience when I purchased a hot dog and knish to go at Ben’s Deli.
After a 12-minute ride home, the hot dog and the knish were cold. I sent an email to the company about their poor choice of using foil wrap and did not receive a response. Foolishly, they still wrap hot food in foil.
Unwrap the pizza and place it in the oven on top of the foil. Heat it to desired temperature. Then, with your bare hand, grab the foil only and drag the slice on to a plate. You will not burn yourself. The foil will have cooled immediately because of its high conductivity. To continue the test, carefully reach under the foil to where the pizza is resting and you will feel the heat as it is conducted away from the hot pizza. Should you not remove the foil, soon you will be eating cold pizza.
Aluminum conducts cold as well as heat. If you would like to speed up the thawing of a frozen steak, simply place it on a sheet of aluminum foil or on an aluminum tray. It will work quickly.
Are you convinced yet?