Why is my pan not suitable for induction cooktops?

The main advantage of induction cooktops is that they only heat the cookware you're cooking with. This makes induction cooking so much cooler: not only can you control the temperature very well, but the cooktops are also very safe, fast, energy-efficient and easy to clean. But the magic of induction also means that you'll need to use special induction cookware, meaning that at least its base is made of a material that has magnetic properties.

The problem is that some of the most commonly used materials for cooking, such as aluminium and stainless steel, do not have this property. But aluminium and stainless steel are two of the most used and valued materials in the kitchen. That is why manufacturers have developed induction systems that allow these items to be used in kitchens of this type.

How do you make aluminium pans suitable for induction?

Getting aluminium pans to be used on induction cookers has not exactly been easy. A ferromagnetic material had to be incorporated into their base so that it activates, absorbs and transmits the energy given off by these types of plates to the entire aluminium body. It seems easy, right? We stick a bit of ferritic steel to the base of the pan and that's it. Well, no.

In order to join aluminium and ferritic steel, two major difficulties had to be overcome – although we will call them challenges, which sounds better. The first is that ferritic steel and aluminium have different thermal expansions, that is, when their temperature changes, their size also changes, but in different proportions. This is a particularly problematic fact, especially if we take into account that a frying pan is basically used for cooking. The second major challenge is that if a very intimate union is made between these two materials – such as welding – the corrosion that is created prevents creating permanent unions.

These two challenges make it very difficult to join aluminium and ferritic steel safely and effectively, whilst still making the pans efficient, i.e. making good use of the heat given off by the induction hob. The first induction bases on aluminium pans that came onto the market fell apart. This happened because the temperature and corrosion caused the ferritic bases to separate from the aluminium.

There are currently various systems for making aluminium pans suitable for induction cookers, although the truth is that not all of them work equally well. A good induction base must be compatible with induction cookers from the main cooker brands. It must also be able to take advantage of and get the most out of the energy given off by induction cooktops. And last but not least, it must occupy the entire diameter of the base of the piece. The system used by Castey aluminium products is called Full Induction and, not only does it activate induction cooktops from all brands very well, but it is also highly energy efficient and has a large surface area.

Stainless steel cookware for induction

Conventional stainless steel cookware on the market uses a system called sandwich to make its parts suitable for induction cookers. This system consists of fixing a diffuser made of a ferromagnetic material to the base of the piece. The main drawback of this technique is that the heat is only transmitted from the base of the piece, wasting part of the energy emitted by the cooktop. In addition, this sandwich can come loose with use.

That is why at Castey we have opted for the Trimetal Induction® system. We manufacture our stainless steel products from a sheet containing three different layers:

• A ferromagnetic stainless steel outer layer that activates induction cooktops.
• An intermediate layer of aluminium that acts as a superconductor, distributing heat evenly throughout the product.
• An 18/10 stainless steel inner layer for a perfect finish. Ideal for healthy cooking.

In this way, the entire product, and not just its base, is able to activate and absorb the energy given off by the plates. In addition, aluminium transmits heat much more efficiently than stainless steel. And by containing it throughout its structure, our kitchen items distribute energy much more efficiently than those made of conventional stainless steel. In addition, they are thicker, so they have great impact resistance and a uniform finish that makes cleaning easier.

Do I need to buy induction products if I don't have an induction cooktop?

Although they are a little more expensive, luckily induction pans and cookware also work on other cooking surfaces, so if you think you will one day have an induction cooktop, it is worth buying induction-safe cookware. This will save you the hassle of having to replace all your cookware at once. On the other hand, if you know you will never want such a cooktop, keep in mind that buying special items for ceramic and gas cooktops will save you a lot of money.

And remember that, although induction hobs have many advantages, they are also a bit fickle. For example, if you don't put the right pans and pots on them, they sometimes don't work and can cause problems. In addition, they need a lot of care and maintenance to keep them working like new.

And if you are thinking of changing your kitchen and switching to induction, our guide to choosing a kitchen will be very useful, as it tells you the main advantages and disadvantages of the main systems.