Is It Safe To Put Aluminum Foil In Your Microwave?

The microwave has made heating up yesterday's takeout or defrosting frozen meals a super easy task. But not everything should go in this handy gadget, including some things you might not expect. For instance, microwaving hard-boiled eggs can cause them to explode, and microwave-safe plastic isn't really a guaranteed thing, due to the chemicals that can leach into your food. Another item you should think twice about putting in the microwave is aluminum foil.

Aluminum foil is made of metal, which reflects the electromagnetic waves produced by the microwave. This prevents the waves from penetrating the food, causing uneven cooking and cold spots. But beyond quality issues, aluminum foil can also pose a huge safety risk. For instance, if the foil is crinkled, little sparks can develop, and the electromagnetic waves can also cause the foil to heat up. Both of these issues create a potential fire hazard, and for that reason, we recommend you avoid using aluminum foil in the microwave.

While it's generally best practice to avoid using aluminum foil, it is possible for very small amounts to be used safely. The key rule, according to the USDA, is that the foil should always be smooth, as sharp or crinkled edges cause an electromagnetic field to build up, which is responsible for "arcing" (the little lightning bolt sparks).

Additionally, some prepackaged foods are manufactured with aluminum foil components. If you are heating a pre-packaged meal that contains foil, always check to see if the manufacturer specifically states it is safe to be put in the microwave. If you choose to use foil to shield small areas of food (e.g., bone ends), cover no more than a quarter of your portion and ensure the foil is smooth and away from the microwave walls. If you notice sparks, immediately stop cooking and turn off the microwave to prevent them from developing further and igniting a fire.

To prevent splatters and keep your food moist, microwave-safe glass or silicone lids are much safer options than aluminium foil. If you don't have these on hand, a damp paper towel can be used to cover the entire portion of food.