Food preservation

How To Keep Food Warm With Aluminum Foil

Aluminum foil has been keeping food sealed and warm for over a hundred years. Since it can be molded to fit snuggly against food and prevents heat from escaping, it has proved invaluable as a strong yet lightweight food covering. Adding a layer of aluminum foil is an effective method to keep food warmer for longer.

To keep food warm, completely cover hot food with aluminum foil. Use an additional piece if the roll is too narrow. Leave a gap between the food and the aluminum foil and secure the edges around the sides of the container to prevent heat from escaping. Provide additional insulation to keep food warmer for longer.

Adding a layer of shiny metal foil over food keeps food warmer for longer, and it has become a go-to in most kitchens. While popping a sheet of aluminum foil over hot food is always helpful, there are some tricks to make it even more effective.

How Do You Keep Food Warm In Foil?

Covering hot dishes with a layer of aluminum foil is a quick, no-fuss way to keep food warm. In addition, it keeps the food hygienically clean and prevents it from drying out.

Keeping food warm using aluminum foil isn’t difficult. Use these five tips when using foil to keep meals fresh and delicious for longer.

  • The aluminum foil should completely cover the food without any gaps on the sides where heat can escape. Use two sheets if the roll is too narrow so the food is completely covered.
  • Cover the dish containing the food with aluminum foil and fold it down around the edges.
  • Leave a slight gap between the surface of the food and the aluminum foil. The foil works by trapping the heat, aroma, and moisture near the surface of the food, so it should never touch the food.
  • When it is unavoidable for the foil to touch the surface of the food, it helps to add a few layers of butter paper. The non-conductive, non-stick butter paper will create a small air pocket between the hot food and the aluminum foil.
  • If you need your food to stay warm longer, add some additional insulators to the aluminum foil. A cooler containing a hot water bottle works well, or wrap the foil-covered container in a thick covering of towels or your picnic blanket.

How Does Aluminum Foil Work?

Aluminum foil is a versatile metallic material made from thin sheets of aluminum that contains a small amount of iron or silicone to provide additional strength. The result is a pliable foil that is easy to wrap around objects.

The shiny kitchen foil works by acting as a barrier to light and oxygen. In addition, the metallic material reflects heat – so long as it isn’t in direct contact with the heat source.

If aluminum foil is placed directly against hot food, it becomes a heat conductor rather than a reflector. Although it works well to trap hot air around the food, it is not an effective insulator.  

The heat from food wrapped tightly in aluminum foil moves into the foil itself. It would escape unless there were some other forms of insulation around the items. When wrapping individual food items like burritos or hot baked potatoes in foil, it helps to place them in an insulated container or bag to keep them warm for longer.

How Long Will Aluminum Foil Keep Food Warm?

Covering food in aluminum foil without adding any additional heat source or insulation will keep it warm for about 30 minutes. It is an excellent option as a short-term covering to keep food warm and appetizing until you are ready to enjoy it.

Aluminum foil can also be teamed up with other containers and insulators to keep food warm for extended periods. If you need to transport a hot cooked meal or want your food to stay warm for later, aluminum foil can be used to transform a regular cooler into a portable insulated container.

How To Turn A Cooler Into A Warmer Drawer

A cooler is usually used to keep drinks cool on hot summer days. Its thick walls are designed to lock in icy refreshments, but an ordinary cooler can easily be transformed into an insulated food storage box for hot meals.

  • To begin, warm the inside of the cooler. Pour hot water into the empty cooler, close it, and wait 10 minutes. Then drain the water and quickly dry the cooler.
  • Line the inside of a cooler with a thick layer of foil. The cooler provides an insulated shell, while the reflective barrier provided by the shiny foil keeps thermal energy trapped near the food. Remember to include the underside of the lid.
  • Add a source of heat. Make heat packs by placing uncooked rice inside new, sealed socks, or heat a few foil-covered bricks in the oven.
  • Wrap each hot dish going into the cooler in a layer of aluminum foil.
  • Fill up any gaps in the cooler with a towel or things you may need, like a picnic blanket.
  • If possible, add a hot water bottle at the top before closing the lid of the hot box.
  • Avoid opening the hotbox cooler until you are ready to use the food.

Which Side Of Aluminum Foil Goes Up?

Aluminum foil has two visibly different sides. One side is super shiny, and the other is dull. Kitchen lore has always dictated that the shiny side should face in to reflect heat onto food, but does it make a difference?

According to Michelin-star chef Tom Kerridge, the shiny side of aluminum foil should always face down to reflect as much heat as possible onto the food. However, according to Reader’s Digest, it makes absolutely no difference which side you choose when wrapping food.

The difference in appearance of the two sides of aluminum foil results from technicalities inherent in the manufacturing process. There is, therefore, no right or wrong side when wrapping food in the shiny protective barrier. Both sides will work just fine.


To keep food warm using aluminum foil, it is essential to maintain a gap between the hot food and the layer of foil. The intention is to create a barrier to trap and keep warm air and moisture around the food.

If aluminum foil is laid directly against the food, it becomes a thermal conductor, and the heat will escape from the outside surface of the foil. Provide additional insulation around the aluminum foil covering to keep food warm for longer.

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