A beautiful fact about stainless steel is that they do not affect the taste of the product. They are easily cleaned and sterilized to prevent bacterial contamination of the food and they are durable requiring minimal maintenance.
Stainless steel is most notable for its corrosion resistance, which increases with increasing chromium content. They are also resistant to staining.
Does stainless steel work on induction?
Stainless steel works on an induction cooking surface if the base of the cookware is a magnetic grade of stainless steel. As stainless steel can be made with a variety of metals, a high nickel content will block the magnetic field. An example of stainless steel working on induction is 432 (which is a type of stainless steel material).
At a skin depth of 24kHz, the resistivity of stainless steel 432 is 24.5 (10-6 ohm-inches), relative permeability is 200 and surface resistance (10-3 ohms/square) is 3.5.
Ferritic stainless steels are made up of ferrite crystals, a form of iron with 0.025% carbon. It only absorbs a small amount of carbon because of its cubic crystalline structure which consists of one iron in each corner and a central iron item, the central atom is what gives it magnetic properties. Therefore, ferritic stainless steel can work on an induction cooktop.
Annealed austenitic stainless steels are usually non-magnetic and maintain their ductility at cryogenic temperatures. They are further subdivided into two groups, 200 series and 300 series which are made up of chromium manganese nickel alloys and chromium-nickel alloys.
Now before going through how stainless steelworks on induction, let us first understand how induction cooking works.
How stainless steel work on induction?
The ferromagnetic properties of a steel vessel concentrate the induced current in a thin layer near its surface, which results in a heating effect.
Because stainless steel is a poor conductor of heat, it is often used as a thin surface cladding over a core of copper or aluminum. This is because aluminum and copper are more conductive than steel.
Such materials are called “tri-ply” with a skin of induction compatible stainless steel with an inner layer of aluminum or copper. “5-ply” cookware materials are also a hit on induction as they have an inner hidden layer of copper. Five ply cookware have a combination of all goodness of metals with the last layer being stainless steel.
This ensures the heat spreads evenly and quickly. Stainless steel pans are available as steel plates pressed into aluminum or a layer of stainless steel over aluminum. The high thermal conductivity of aluminum makes the temperature more uniform across the pan.
Stainless steel cookware should also have a flat bottom since the magnetic field drops rapidly with distance from the surface.
For the stainless steel cookware to cook efficiently, it must be of the same size as the ring of the cooktop.
Testing for compatibility
Many manufacturers have started putting an “induction compatible” symbol on the bottom of their cookware. The symbol often looks like a horizontal zig-zag or a coil. Some have the word “induction” written on it.
The higher the surface resistance of the cookware, the more the heat that will be produced. This can be used to test the suitability of the cookware materials to be used on induction.
Take an ordinary fridge magnet and check for compatibility with an induction cooktop. If the magnet sticks to the bottom of the cookware, it is induction compatible.
If the magnet grabs the pan softly, you may not have a good success cooking with it on induction
If the magnet does not cling, the stainless steel cookware is not of a magnetic grade.
Health effects of Cooking in Stainless Steel
Stainless steel is generally biologically inert, but some sensitive individuals develop skin irritation. This is due to nickel allergy caused by certain alloys.
Stainless steel leaches small amounts of nickel and chromium during cooking.
In one 2013 study, scientists tested the leeching of nickel and chromium into foods cooked in stainless steel pans. The study tested the stainless steel leaching into tomato sauce over periods of 2 to 20 hours.
The findings found were as follows. Longer duration of cooking increased leaching. New stainless steel leached more than pans that had been used prior to testing.
The science behind induction cooking
A coil of copper is placed underneath the area to cook and an alternating current is passed through it. This creates an oscillating magnetic field.
This magnetic field penetrates the bottom of the cookware and induces large eddy currents which produce resistive heating in the cookware. This leads to heat generation and the cooking of food.
Induction cooking has good electrical coupling between the cookware and the cooktop and is thus quite efficient. This means it puts less heat waste into the kitchen.
It is also more responsive to changes in temperature control and can be switched on and off quickly.
Only the part beneath the cookware gets hot and the rest of the cooktop remains cool to touch. This makes it safe to use and easy to clean.
In order for any cookware to perform on induction, it must be ferromagnetic or have a layer with magnetic properties at the bottom.
However new advancements have brought forward different methods to bring about induction compatibility without iron or magnetically conductive layer being present.
For example, new types of power semiconductors and low loss coil designs have made an all-metal cooker possible. Panasonic in 2017 developed an all-metal unit and named it “Met-All”.
The best thing about using stainless steel for induction is that stainless steel is 100% recyclable! An average stainless steel object is composed of about 60% recyclable material. What prevents a higher recycling content is the availability of stainless steel scrap.
Another plus point for magnetically conductive stainless steel is that it can nearly always be used on other stoves.
With a high resistance to corrosion, lower maintenance and compatibility with all cooktops, the magnetic grade of stainless steel is an ideal choice in a triply or five-ply designed cookware. Enjoy greater efficiency and a great taste with your stainless steel on induction!
You may also like the following articles about induction cooking:
- Can Induction Cookware be used on Gas Cooktops?
- 10 Best Non-Stick Pans for Induction Cooktops
- Best Griddle for Induction Cooktops
- Best Induction Cookware For Your Kitchen
- Best Tea Kettles for Induction Cooktops
- Will a WOK work on an Induction Cooktop?
- Does Cast Iron work on Induction Cooktops?
- Will Granite rock pan work on an induction cooktop?
- Ceramic vs. Stainless Steel Cookware – Which is Better?