Can You Use Aluminum Foil to Keep Food Warm?

Think back to how your refrigerator looked the day after a party, or on Boxing Day morning. Chances are, upon opening the door, you were greeted by piles of aluminum foil parcels, each containing tasty morsels from the day before. So this may make you wonder; if foil is good for preserving food for future use, could you also use it to keep food warm after cooking? The answer is yes – and here’s how.

Using Foil to Keep Food Warm

Aluminium is a conductor of heat, meaning that it allows heat to pass through it. However, its shiny surface reflects some of the heat back. This reflectivity is why fast food outlets often use aluminum trays when making home deliveries – there’s more chance of the food still being warm when the food arrives. 

Adjusting the Effect

If you first wrap the food in a napkin, and then wrap it in aluminum foil, you create an extra layer of insulation that will keep the food warm for longer. If you wrap once again with plastic film, you’ve created a third layer for an even greater effect. Another approach is to wrap the food in a napkin, and stand it on top of a sheet of aluminum foil.   

Safety Concerns

Have you every wrapped some food in foil, put it in the oven, and then found that you could touch the foil without burning your fingers, even though the food is piping hot. Aluminum foil is an ideal choice for this purpose because it has a low heat capacity. In other words, it can’t store a lot of heat. So, while it can still reflect the heat and keep it inside, it is usually safe to handle – unless it gets very hot of course, and even then it will tend to cool down fairly quickly.

It’s also important to remember that cooked food should not be kept warm for longer than 2 hours, whether using foil or any other method. After this time, food should be refrigerated in order to prevent bacteria growth, and should not be reheated again.

And there’s your answer – yes you can indeed use aluminum foil to keep food warm, and it’s a handy trick to keep in mind if you’re cooking a meal and got your timing off a little bit, or if your guests are going to be delayed a little. Happy cooking!