Before I discovered induction cooking, I thought that the only way to heat a pan was by using a hot stove. Either you blasted it with burning gas, or you cooked it on an electric ring. Those were your two options.
So you can imagine how awe-struck I was to hear that there was a third possibility – induction cooking – that didn’t involve heating my stove at all. It seemed to defy the laws of physics. How fabulous!
What Is An Induction Cooktop?
An induction cooktop is just a cooking surface that uses induction technology to heat the pan. Traditional stoves heat pans using thermal conduction and convection. The cooker creates heat, either in the form of a flame or a hot ring and then passes it into the contents of the stove above. Fast-moving atoms in the stove transfer their energy to particles in the pan and the food you’re trying to cook, warming the whole ensemble.
Induction cooktops are fundamentally different. They work using a whole other branch of physics. The induction cooktop itself doesn’t provide the heat. Instead, it uses the principles of magnetism and electrical resistance to warm the pan above. The hob remains bizarrely cool to the touch when switched on, running counter to your intuition.
How Does An Induction Cooktop Work?
Have you ever held onto an insulated electrical wire while a current is passing through it? If so, you may have noticed that the cable starts to get warm. The reason for this is that electricity doesn’t pass through wires without resistance. Even in copper, electrons can get stuck, releasing their energy and heating the surrounding material.
Usually, resistance in wires is a bad thing. But scientists realized that they could take advantage of the properties of it to create a new way to cook. Electrical resistance is precisely what makes an induction hob work.
Of course, induction hobs don’t pass an electrical current through your pan – that wouldn’t be safe. Instead, they work by heating it indirectly using magnetic fields.
The functioning part of the induction hob is a coil of copper wire. The hob passes an alternating current through the copper wire to generate a magnetic field. The magnetic field then wirelessly transmits electric current into the pot above, creating eddy currents.
These eddy currents circle around in the pan above according to the shape of the magnetic field and create resistive heating. It’s the same phenomenon as in the copper wire. The current doesn’t flow perfectly freely through the pan material. Some of the electrons release their energy into the surrounding material, exciting neighboring atoms and heating them.
If you turn on an induction hob and leave it running, it will never get hot. All it’s doing is creating a magnetic field. However, it’s not entirely correct to say that induction hobs never warms. They do, but for different reasons than a regular hob.
In the case of induction cooktops, the hob heats the pan, and then the heat energy in the pan conducts back down to the hob, heating it indirectly. You can, therefore, still have an induction hob that’s too hot to touch, even if the hob itself doesn’t generate any heat.
Induction Cooking Requires Special Pans
One of the quirks of induction cooking is the fact that you need special pans. You can’t just whack any old cooking vessel on the hob and expect it to heat up – it won’t. You need a pot that can interact with the magnetic field generated by the induction hob to create heat.
Silicone pans are out. So too are enamel. Even aluminum and copper pans don’t work.
If you want to use an induction hob, you have to use pans with high ferrous metal (iron) content, such as cast-iron of stainless steel. Iron concentrates the electrical energy generated by the magnetic field and provides the resistance that current needs to create heat. Copper and aluminum don’t do this.
There’s another point to make: you also need pans of the correct thickness. If your cast-iron pan is too thin, there isn’t enough space for the current to flow and it won’t provide the conditions for resistive heating. So, if you’re looking for pans to go on your induction cooktop, look out for heavy-set, bulky cookware.
The Benefits Of Induction Cooktops For Chefs And Amateur Cooks
Induction cooking isn’t just a gimmick. It offers a plethora of benefits for chefs, some of which will make you wonder why you didn’t start using induction cooktops before. Let’s take a look at them now.
Adjust The Temperature More Quickly
Boiling a pan on an electric hob is no fun. You’re often waiting for ten minutes or more before the water begins to simmer – longer if you’re cooking for a large group of people.
Cooking on a gas-fired stove is better: water will usually begin to boil after a few minutes. But nothing can quite compare to induction cookers for the speed at which things cook.
Restaurant guys love induction hobs. They allow them to bring water to the boil in less than a couple of minutes and get straight on with cooking so that customers don’t have to wait. Typically, induction cooktops are between four and six minutes faster at boiling pans than their conventional alternatives.
Get More Precise Control Over The Temperature
Sometimes when cooking, you need to exercise precise control over the temperature of the contents of the pan. Doing that with either electric or gas is a challenge. There’s a delay between changing the temperature on the dial and the heat in the pot going up or down.
With induction hobs, however, the change in temperature is much faster. The magnetic field heats the metal on the bottom, sides and, sometimes, the top of the pan, providing a warming surface from multiple directions.
Cook More Safely
While the surface of the induction hob does heat up during cooking (owing to the convection of the pan above), it won’t heat up when left unattended. A chef could put his or her bare hand onto the hob after accidentally leaving it running and not experience any burns at all.
There’s also no risk of fire, as there is with a gas hob, making it ideal for busy kitchens.
It Uses Less Energy
The problem with gas and electric ring cooking is that both waste a substantial quantity of energy. While a fraction of the heat they create goes into the cooking vessel, a lot of it is lost to the surrounding environment. The average gas hob heats the surrounding air in your kitchen as much as it does your pans.
Induction cooktops, however, convert the vast majority of their energy into electrical resistive energy. The pan then conducts this energy into the contents, with less energy lost to the surrounding environment. Research indicates that induction hobs transfer an impressive 84 percent of the energy they use into the pan above, around 10 percent higher than the best electric hobs on the market.
It’s Easy To Wipe Clean
Finally, wiping induction hobs clean is generally easier than it is with other types of cooktop. Because induction hobs never reach extreme temperatures, food debris doesn’t burn onto the surface. Often, it doesn’t even reach boiling point, making it easy to wipe up with a towel once you’ve finished. No scrubbing brush required!
What About The Cost?
Okay, you might say, the benefits sound great, but nothing is free. What about the cost?
Induction cooktops tend to cost slightly more than conventional alternatives to buy outright, but prices have been falling for a long time, and continue to do so. When included in a cooker with the cost of fitting including, you’ll struggle to notice any difference at all.
What’s more, the data suggest that you’ll spend around 40 percent less running an induction cooktop compared with a regular electric hob.
Gas remains the cheapest option in terms of running costs because of the low price of fuel.
So what have we learned about induction hobs?
Well, the most exciting thing that we’ve discovered is that there is a way to heat pans that doesn’t involve the direct transfer of heat energy. By taking advantage of the resistive properties of metal, induction cooktops create a heat source that doesn’t involve any flames or hot elements at all. A simple magnetic field will do.
We’ve also discovered that induction cooktops offer a host of advantages over traditional cooking surfaces. They’re more efficient, easier to clean, use less energy, and are safer.
If there are any downsides – and you’d be pushed to find them – it’s that induction hobs still can’t quite compete with gas in terms of price. There’s also the slightly annoying fact that you might have to buy new pots and pans that are induction-compatible. For chefs, though, the instant heat is a godsend and something that many of the best kitchens in the world use to speed up their cooking.