One of the worst mistakes you can make in preparing food at home is putting any kind of foil in a microwave. It has been well-documented, but it always bears repeating for the uninitiated: Foil and metal in the microwave will always start a fire. So, the question becomes: Does foil in an air fryer meet the same fate?
The short answer is that yes, you can put foil into an air fryer. Basically, anything that can go into a normal kitchen oven can go into an air fryer. But naturally, it is not so simple as that. Air fryers are built slightly differently than ovens, and as such a few extra precautions are needed to use them safely.
How An Air Fryer Works And Why It Matters
When understanding air fryers, it benefits you to think of them in comparison to conventional kitchen ovens: A conventional kitchen oven has a heating element that is either electric or a flame generated by gas. Kitchen ovens will also usually (but not always) have a fan that helps circulate heat around the inside of the oven.
Air fryers are similar in that they will have a heating element and a fan, but with two key differences: First, the heating element will basically always be electrically based. This makes a lot of sense when you consider the next point, which is that the heating element will always be located near the fan.
This means that if the heat did come from a flame, the flame would likely get displaced by the air and extinguished. It also means that air fryers heat their food more intensively and directly since the heat is being directed onto the food rather than just sitting ambiently in the oven. There are downsides and upsides to this.
The upside of this method is that it happens way faster. Microwaves are usually used to make cooking fast and easy, but they have the drawback of heating things in a very particular way that makes the food lose a lot of texture. Air fryers find a middle ground that makes them quick and easy, while still preserving texture.
The downside to the way an air fryer heats things is that it can crisp things and brown them, but it has to be used very carefully if you want to cook things all the way through. This is not to say an air fryer cannot cook things all the way through; it absolutely can. But you have to be careful when doing so.
One of the best methods for cooking things all the way through in an air fryer is by wrapping them in—you guessed it—foil. And here is where the extra precautions come in.
The Extra Precautions
The first and most important thing to remember when putting foil in an air fryer is that the foil must not rest on or near the heating element. This means you can put it in the basket, but not in the drawer. You cannot risk it getting blown somewhere which results in it absorbing more heat than you want it to.
But most people have no issue keeping foil from “blowing around”. In fact, they may see those two words and think “How would that even happen?” Normally, it will not happen. Because normally, the foil will have something weighing it down, like food. But it is also possible for abnormal things to happen.
Imagine that you have a sandwich in the air fryer. It has aluminum foil around it, naturally, and is being heated up. But it is not one continuous piece of foil. It is two pieces of foil, one on top and one on the bottom. Now, it is possible to do this safely by wrapping the top piece around the bottom of the sandwich to weigh it down.
But even then, this just means that your sandwich is wrapped in a piece of foil shaped like a C, and that piece of foil could easily be unwrapped if the fan was blowing on the inside curve of that C shape. More likely, however, your wrapping really is two distinct pieces of foil. In that case, the foil can blow right off.
In short, there are actually many ways to wrap something in foil in an insecure way. These do not matter in a normal kitchen oven, but they absolutely matter when using foil in an air fryer. So, be careful.
How Hot Does Foil Need To Get Before It Catches Fire?
Every material in existence has a property called “conductivity”. Conductivity is the material’s ability to convey energy through itself. Imagine you are trying to get electricity from one end of the room to another. Rubber would not be able to transfer that electricity. Metal would do so the best.
Metal is more conductive than basically any other material. Aluminum foil is included among those metals, even though it is so thin it might not seem like a metal at first blush. Metal can contain and pass on more heat than your average material.
Why is the conductivity of metal important? Well, because microwaves utilize something called “microwave radiation” in order to heat food up. This radiation is sent into the food, or whatever else is in the microwave, heating it in accordance with its conductivity.
Now compare a microwave to a normal oven. Whereas an oven can only heat up metal so much (the metal will become too hot to touch, but not much worse than that) a microwave will keep heating and heating and heating and heating the metal until it combusts. Tons of heat will be pushed into this metal.
What is the combustion point of aluminum? The answer is around 2400 degrees Celsius. That microwave radiation keeps heating the metal more and more till it catches fire. Eventually, the aluminum explodes in your microwave, doing so with the heat of a hand grenade.
Air fryers are far less likely to cause the aluminum foil to ignite, but it is possible. It does not take long for a 300 degree jet of heat to pile 2400 degrees into a piece of aluminum, especially if that piece of aluminum is stuck to the heating element or the fan somehow.