Mark for induction-suitable cookware

The pots with the "spiral": How to recognize cookware that is suitable for induction cookers

Induction plates have by far the highest energy efficiency of all stoves: Because the heat is generated directly in the base of the cookware, there is little heat loss. Accordingly, an induction hob does the same job faster and with around 20 percent less electricity than a ceramic hob, around 40 percent less electricity than an old cast iron stove top - and with only half as much energy as a gas stove!

However, you can only cook on induction hotplates with induction-compatible cookware. What makes such pots special - and above all: How can I tell whether my tried-and-tested pot and pan set is also induction-compatible?

How do I know if pots and pans are suitable for induction?

Modern cookware that is suitable for induction cooktops has a small pictogram of a spiral in a square on the bottom – usually alongside other symbols that indicate suitability for other stove types: This is the spiral symbol for induction. You don't have to search long for such products. The sign can be found on almost all modern pans, pots and casseroles from IKEA to Le Creuset - after all, the manufacturers don't want to put obstacles in their own way. And since induction pots and induction pans are also suitable for ceramic hobs and gas stoves, most cookware today is simply made of induction-compatible metal.

But what if you have older or exotic pots that are not so marked? In this case, you can test the suitability of the candidates with an ordinary magnet. Cookware that is suitable for induction must have a ferromagnetic layer at least on the bottom. "Ferromagnetic" means nothing more than the property that we refer to as "magnetic" in everyday life, i.e. materials that are attracted to a magnet. This results in the simple test of induction suitability: If a magnet sticks to the bottom, you can also use the pot or pan on induction plates. The ultimate test is of course always the practical test: does the pot get hot on the stove? Nothing can happen - unlike with other types of stoves (and microwaves!) you can actually put all kinds of crockery from aluminum to plastic on an induction plate without it becoming in any way dangerous.

What happens if I put a non-induction pot on the induction cooker?

If you place a non-induction pot on an induction plate, nothing happens. The pot does not get warm. Don't worry - nothing can break at all. The stove doesn't mind, there are no sparks, the fuse stays in and the pot stays intact.

To make you aware of your error, most induction cooktops have sensors that detect that nothing is happening in the pot and activate a beeping and/or flashing signal.

Which materials are not suitable for induction?

Aluminum, cast iron, earthenware, glass are unsuitable from the outset - and unfortunately also most of the types of stainless steel that were common for cookware in the pre-induction cooker era. The same applies to old copper dishes.

Of course, the manufacturers of modern copper, cast iron and stainless steel cookware also think of the owners of induction plates - after all, anyone who buys an expensive stove often also invests in high-quality cookware. Accordingly, copper and cast-iron pot and pan sets today actually always have ferromagnetic induction bases. The symbol for induction is the sign of the spiral - just pay attention to this when buying a pot.

How can I use old pots on an induction cooker?

If you do not want to use induction-compatible crockery on an induction hob, you can purchase a so-called induction adapter plate. This ferromagnetic plate heats up when you place it on the induction cooker. On top comes the pot - and you then have practically a classic hot plate under your heirloom made of copper, earthenware, aluminum or cast iron.

However, this slows down the energy efficiency of your induction plate: With an induction adapter, heat losses come into play again, and your state-of-the-art energy-saving stove is no longer quite as fast and energy-saving.

What is the difference between a ceramic hob and an induction hob?

For the sake of completeness: Ceran is actually the brand name for a certain type of glass ceramic - which has become common for all stoves with a glass ceramic surface. However, induction cookers also have a glass-ceramic surface (which can even be ceramic), so that, strictly speaking, the distinction between induction and ceramic no longer makes any sense at all - actually, the ceramic hobs are technically more meaningful than halogen hobs. But of course we will stick to the usual terms here.

When switched off, the ceramic hob and induction hob are almost indistinguishable. Only when one of the plates is switched on can you tell which cooker is which: the plate on the ceramic hob starts to glow red and heats up very quickly, while the induction plate doesn't seem to do anything and doesn't develop any heat. Only when a suitable pot is placed on the induction plate does it heat up - while the plate remains cool.

Technically, ceramic and induction hobs differ in what lies beneath the shiny glass-ceramic surface. In the case of ceramic hobs, this is a special heating coil filled with halogen gas. When the power is switched on, the heating coil emits thermal radiation and a small amount of red light. The halogen heating element works according to the same principle as a halogen lamp - only that the emitted radiation is mostly in the wavelength range of invisible infrared heat radiation. This thermal radiation penetrates the glass-ceramic surface of the cooker and heats the pot. The specific material of the pot - as long as it is heat-resistant - is irrelevant.

In the case of the induction field, there is one or (in the case of stoves with surface induction) several closely wound spirals of copper wire under the glass ceramic. If current flows through these spirals, practically no heat is generated, since copper has a very low electrical resistance. (In contrast, the current-carrying heating elements inside the classic cast-iron griddle contain a long wire with a very high electrical resistance, which converts a large part of the electrical energy into heat.) The copper spirals of the induction field emit hardly any heat, but instead a pulsating electromagnetic field . If you bring a ferromagnetic material into the area of ​​influence of such an alternating field, electrical eddy currents are excited there (the physical term for this is induction). If the ferromagnetic material has a high electrical resistance, the eddy currents generate heat. This is exactly what you take advantage of with induction pots: the ferromagnetic bottom of the pot heats up due to the eddy currents. Induction pots and induction pans practically have their own hob in the bottom! Pots that aren't magnetic, on the other hand, won't work on an induction plate.

Induction or ceramic? When is an induction cooker worth it?

Induction cooktops generally cost a little more than ceramic cooktops, but have now become significantly more price-competitive. In other words: a cheap induction hob can already be cheaper today than a more expensive ceramic hob.

In this respect, a cheap induction cooker can also be financially worthwhile - as long as you don't have to replace all the pots and pans. And as long as the stove doesn't break - induction plates are full of sensitive electronics. Especially cheaper specimens can be quite vulnerable. If everything goes smoothly, you save about 20 percent of the electricity costs of a ceramic hob. With an output of 4 kilowatts, an average of one hour of operation per day and an electricity price of 30 cents per kilowatt hour, the annual saving is almost 90 euros.

You have to decide how important this amount is for you financially. Such an energy-saving stove may at least bring with it a somewhat better environmental conscience.

In principle, an induction hob is always worthwhile if you really benefit from the practical advantages of this type of stove. Do you cook a lot, like and ambitiously? With an induction cooker, things are much faster and, above all, more precise. Temperatures can be regulated precisely and extremely quickly. And: In the low-temperature range, an induction field offers unrivaled precision.

Carrying a nostalgic love of tea kettles in your heart? The induction plate is the first electric hotplate that can actually compete with an electric kettle when it comes to heating water. Goodbye ugly kettle!

You like it practical and clean? Because the hob does not get hot, overcooked food on induction plates does not burn. If you cook a lot and sometimes get distracted, the easier cleaning is definitely a plus.

Got clumsy / very curious / death-defying little kids? The plates of an induction hob do not get hot if you accidentally switch them on and stay cool during and after cooking. (The dangers of hot pots are of course not averted.)

Does an induction cooker also have disadvantages?

Apart from the slightly higher costs and the fact that you may not be able to continue using all of your pots and pans, induction hobs do not actually have any major disadvantages.

The noise generated by these cookers might be worth mentioning: some people are annoyed by the noise of the fan, which keeps the electronics cool during operation. And the electromagnetic vortices in the cookware can also lead to a background noise of humming, whistling, clicking and buzzing that is unfamiliar to those unfamiliar with induction. Nothing to worry about - but a bit irritating when you first experience it.

Sometimes, however, it is suggested that induction cookers could be harmful to health. The question of whether induction cooking can be harmful deserves a balanced answer. It is true that millions of people are now doing this - apparently also so far without prejudice - but there are still a number of experts who do not take the security of the technology for granted, at least from the outset.

Can induction cookers be harmful?

The BUND rates induction plates as particularly intense sources of magnetic fields in the home, and the Federal Office for Radiation Protection states that applicable limit values ​​for exposure to electromagnetic radiation can certainly be reached or even exceeded if you are too close to the stove, the cooking zones are not completely covered by the pot or pan or cookware with an uneven base is used.

However, most doctors consider the risk to be far overestimated. Anyone who keeps a normal distance from the stove, places pots as precisely as possible on the plate and does not operate the front stove plates for hours with the particularly energy-intensive booster function is probably not taking any particular risks.

However, there is one exception. Pacemaker wearers should consult their doctor before purchasing an induction cooktop. And to be on the safe side, increase the distance to the active plate even further - there are some reports in the medical literature about interactions between induction cookers and pacemakers. Medtronic, a major manufacturer of pacemakers and implantable defibrillators, recommends a minimum distance of 60 centimeters. In addition, pacemaker patients should not use a metal spoon to stir, as this conducts small currents from the bottom of the pot through the body and could, at least theoretically, also affect a pacemaker. (On the other hand, you cannot get a really noticeable electric shock when touching an induction pot - the warning really only applies to people with highly sensitive electronic implants!)


FAQ

What is the sign for induction?
On the bottom of induction pots and pans you will find the spiral symbol for induction: a small pictogram representing a spiral inside a square.


How else can I tell if a pot is suitable for induction?
If a magnet sticks to the bottom of the pot, you can use the pot on induction plates. Don't have a magnet handy? Just try whether the pot gets hot - nothing can happen.


How can I use non-induction pots on an induction cooker?
There are so-called induction adapter plates for this. They go on the stove and the pot on top.


What are the advantages of an induction cooker?
Induction cookers save energy, they heat up food faster and can be regulated more precisely than all other electric cookers: for example, water stops boiling as soon as the plate is switched off. In addition, induction hotplates do not get hot and there is no danger if a plate is accidentally switched on or not switched off after the pot has been removed.


What is the difference between induction and ceramic hobs?
Ceran hotplates heat the food to be cooked using the radiated heat from a halogen heating spiral underneath the glass ceramic surface. Induction plates generate an alternating magnetic field that induces eddy currents in the bottom of the pot, which generate heat directly in the pot.


Are induction cookers harmful to health?
Induction cookers emit electromagnetic radiation - just like many other household appliances. The stoves are only approved if they comply with the applicable limit values ​​for exposure to electromagnetic radiation when used as intended. If you keep a distance of at least ten centimeters from the stove, use the booster function on the front plates sparingly and place pots precisely on the plates to minimize stray fields, you are not taking any risks. And even exceeding the limit values ​​for a short time is not really a cause for concern. A certain risk awareness actually only makes sense if you work a lot with induction cooktops – or if you have an implanted cardiac pacemaker. In the latter case, you should consult your specialist before purchasing the new cooker.


Sources

https://de.wikipedia.org/wiki/Induction cooktop
https://de.wikipedia.org/wiki/Halogenkochfeld
https://kueche.de/kuechenwissen/elektrogeraete/kochfelder/induktionskochfeld/#c16013
https://www.weltderphysik.de/thema/hinter-den-dingen/physik-des-induktionsherdes/
https://www.br.de/radio/bayern1/induction-vs-ceran-100.html
https://www.br.de/radio/bayern1/inhalt/experten-tipps/umweltkommissar/wasser-wasserkocher-energie-umwelt-100.html
https://www.bfs.de/DE/themen/emf/nff/application/induction cooker/induction cooker_node.html
https://www.baubio-ologische.de/induktionsherd-und-gesundheit/
https://www.medtronic.com/uk-en/patients/electromagnetic-guide/household-hobby.html
https://therationalkitchen.com/induction-cooking-safe/
https://academic.oup.com/europace/article/8/5/377/460579
https://www.medical-tribune.de/medizin-und-forschung/artikel/induktionsherde-belasten-den-koerper-offenbar-kaum/