The rest of the cooking happens by conduction. According to the United States Department of Agriculture (USDA), you can put small amounts of tin foil in the microwave to use as a shield on some parts of the food (e.g., poultry drumsticks and wings), which you do not want to overcook. They can penetrate through food, but only a few inches deep. Food in aluminum trays can be heated up in a microwave unless the contrary is stated by the manufacturer. You don’t want them to rub against the walls while rotating, as that could cause some issues (like sparks). Weird & Wacky, Copyright © 2020 HowStuffWorks, a division of InfoSpace Holdings, LLC, a System1 Company. Sparks May Form Regardless of the Use of Aluminum Foil. If you completely cover your food in foil, it simply won’t heat up. The metal walls of your microwave oven are there to reflect the microwaves and keep you safe from them. The thing some people find strange is that there are two usual outcomes of the tin foil experiment. The aluminum baking trays in which you receive your takeout food, for example, are safe to microwave. Do not cover more than 25% of the food with foil. Take the extra time to make sure everything is nice and smooth before you toss it in your microwave oven. Firstly, it is important to note that the walls of microwaves are made of thick metal. The following describes the proper use: Aluminum foil is used to shield portions of a food item to prevent overcooking. This one should be pretty obvious, considering that edges that stick out cause sparks. Spoiler alert — they don’t. Consequently, it heats up immensely and forms sparks. They save us time, make cooking/heating up food more convenient, and take up very little space in comparison to regular ovens. But for the sake of it, let’s pretend you decided not to listen to common sense and tried to follow the trend. If there are pieces of foil that can come in contact with the sides, however, quickly fold and smooth them out. That’s dangerous and could cause accidents. What Happens When You Put a Wrinkled Ball of Aluminum Foil in the Microwave? Well, the USDA says it doesn’t matter. As you gain some experience, you’ll know exactly how much foil you need, depending on the dish you’re heating up. Needless to say, that goes against the laws of physics (and common sense), but still, there were thousands of people who decided to try it for themselves. Again, that depends on the specific oven you have, so read the instructions. Rules for Safe Use of Aluminum Foil in a Microwave Oven. They excite its molecules, which naturally produces heat, and voilà; you get the perfect mac ‘n’ cheese in a matter of minutes! Now back to the real question- why can’t you put aluminum foil in the microwave? Yes, microwaves are harmful to live organisms. There are plenty of videos on the internet, so if you’re curious, check them out; it’s safe and free…. This is common enough that you sometimes see microwave cookbooks recommending that people shield wing tips and other easily-burnt parts of food with a little foil as they cook. Foreseeably, that resulted in a few broken microwave ovens and loads of disappointment…. If you’re heating up meat, for example, you can use wooden toothpicks to hold thin strips of foil over the thinner parts. Because aluminum foil is thin, it isn’t able to reflect microwaves, and can’t covert it to … Those include dense vegetables, like raw carrots, spinach, beans, etc., and even hot dogs. If your tray is more than three inches deep, you risk getting the top of your food heated while the bottom remains cold. There is always some room for error. That’s why I’d say don’t take your chances, and remove the foil shielding you’ve created if you spot sparks/flames. Stay safe and bon appétit! Simply transfer your food to a microwave-safe container. To help you, here are the points the USDA makes for safe use of foil in the microwave, as well as some additional tips worth mentioning. It started as a joke — people were pretending that they could turn a crumpled ball of foil into a perfect reflective sphere just by placing it in the microwave for a few minutes. Microwave ovens are one of the greatest inventions of our era. All the sharp edges, which are very hard to avoid, can cause sparks. However, the USDA also recommends checking the owner’s manual of your microwave just in case. Related post: Can You Put Aluminum Foil in a Regular Oven? The metal acts almost like a shield or a mirror, reflecting the waves and preventing them from escaping from the microwave. Microwave Ovens and Food Safety; Metal in the Microwave; Aluminum Foil does NOT Go in the Microwave Therefore, try to only cover areas that may burn. Essentially, the oven produces microwaves (electromagnetic radiation) that get reflected by its metal interior and end up being absorbed by the food. Information about the device's operating system, Information about other identifiers assigned to the device, The IP address from which the device accesses a client's website or mobile application, Information about the user's activity on that device, including web pages and mobile apps visited or used, Information about the geographic location of the device when it accesses a website or mobile application. Thus, you can comfortably let the thicker portions get nice and warm without drying out/burning the thinner ones. There are many dos and don’ts when it comes to using aluminum foil in the microwave. In the best case scenario, there will be absolutely no problem from using aluminum foil in the microwave. We also share information about your use of our site with our social media, advertising and analytics partners who may combine it with other information that you’ve provided to them or that they’ve collected from your use of their services. At one point or another, you’ve probably been told to never put aluminum foil in your microwave, unless you want to cause a fire. Some foods are also prone to creating sparks. Again, you should avoid contact between two metals at all costs. That happens because the electric currents formed by the microwave oven overwhelm the foil (which, unlike the walls of the oven, can’t handle them). When caught early, sparks should not cause any problems, but if left alone, they can damage the oven. That’s dangerous and could cause accidents. The same rule applies to foil containers that cause such problems.