Last updated on May 7th, 2024
Hello, curious kitchen adventurers! Today, we’re addressing a widespread myth: the danger of putting metal in microwaves. Contrary to popular belief, it’s not always a strict no. In fact, if you’ve ever microwaved a frozen pizza or a ready meal, you’ve likely already safely microwaved metal without even realising it. Let’s dive into why this metal myth persists and when you really can microwave metal.
What Happens if you Put Metal in a Microwave?
Microwave ovens heat food safely by energising water molecules in the food placed inside. When you try to microwave metal alone, because it contains no water, it reflects the microwaves rather than absorbing them like food does. In fact, microwaving metal without any food is essentially the same as running the microwave empty, which will also cause arcing and sparks. The reflected microwaves will “build up” leading to sparks or arcs, akin to mini lightning. This arcing can damage the microwave’s interior and be a fire hazard. If you only put a metal spoon in a microwave it will definitely spark, but if the metal spoon is in a bowl of soup, it probably won’t because the microwaves have somewhere else to go once reflected by the spoon – into the soup. However, the spoon can still get very hot, posing a burn risk similar to a spoon left in a pot on the stove.
Can I Put Metal in a Microwave?
Yes. You can put metal in a microwave so long as the metal doesn’t have sharp points that are close to one another that can create an arc. Think the tines of a fork, a serrated knife, or crumpled foil. Thicker smoother pieces of metal are generally safe inside a microwave. A spoon, metal cup, metal plate or even metal microwave oven racks are perfectly fine because everything is smooth and rounded off. Foil can be used carefully, as long as it’s not crumpled, and Sharp even recommends using foil to shield parts of food to avoid overcooking in their microwaves. LG on the other hand, is more cautious with a strict no-metal policy in their microwaves.
In some cases, food manufacturers cleverly incorporate metal into microwavable packaging to enhance the cooking process. Microwave pizzas often sit atop foil-lined cardboard, which helps the base become crispy. Microwavable soups often come with a thin metallic layer beneath a non-metallic lid to evenly brown the top layer of the soup. Some frozen dinners use metallic film inside the box to facilitate even heating, ensuring the food cooks thoroughly and evenly. These strategies help direct the heat properly, improving the microwaving experience by ensuring better browning or crisping of the food.
It is Usually Safe to Put Metal in a Microwave but Best Avoided
Generally, it’s best to avoid metal in the microwave unless following specific manufacturer instructions or using microwave-safe metal objects or packaging. Personally, I’ve microwaved metal in my LG microwave without issues. I find it inconvenient to remove cutlery before reheating food, as there’s often nowhere to put it down without it getting dirty. Even though a knife and fork is precisely the type of thing you’re told not to put in a microwave, leaving it on a plate while reheating my food has never caused an issue for me.