How It Works: The electric cooktop

The 1893 Chicago World’s Fair was known for the innovations and firsts it brought to the world: Fairgoers reached new heights aboard the first Ferris Wheel, the precursor to the zipper (called the clasp locker) was displayed, and the electric stove proved that electricity could replace hearths in American homes.

The first electric stove ran a current through large iron plates, which then transferred the heat to pots and pans. Decades later, coils replaced the iron hot plates, and cookware was heated directly on top. In the 1970s, manufacturers redesigned electric cooktops by placing glass-ceramic, including SCHOTT’s CERAN, on top of electric burners to create a flat cooking surface, and glass-ceramic took over as the ideal surface for electric cooktops.

Electric Intro
Today many use electric cooktops daily, but few know the science behind how they work and thus how to get the most out of their electric range. Here’s what happens every time you turn on your glass-ceramic electric cooktop and how to maximize its energy efficiency.

How electricity becomes a heat source
Electric cooktops offer chefs consistent heat flow and 70 percent energy efficiency. Because of glass-ceramic’s low heat conductivity, heat is more confined to pots and pans on the cooking zone, which localizes the heat to the cooking area and keeps the rest of the cooktop cooler. Here’s how it works:

1. Beneath the glass-ceramic surface, electrical current flows through a unique metal coil. Electrical resistance heats to generate a hot glowing metal coil that transfers its heat through the glass-ceramic via infrared energy and to the glass-ceramic via convective heat.

2. Because of glass-ceramic’s low thermal expansion and infrared transmission and emission characteristics, the pot or pan on the cooking zone is warmed evenly by the energy transmitted through the glass-ceramic to the cookware.

Electric Inside

3. Food is cooked by the transfer of heat from the cookware. The surrounding surface of the glass-ceramic remains relatively cool.

4. The glass-ceramic cooktop continues to emit heat after electricity stops flowing, and this residual heat can be used to continue cooking or warming food. An electric light on the stove indicates whether cooking zones are still hot from the cooking procedure.

Be a pro in the kitchen with these tips
Even if you use an electric stove every day, some of the finer points on how to draw peak efficiency out of your cooktop might go overlooked. But a bit of knowledge and insight will help you boil water for pasta and simmer your sauce with perfect temperature control. And after your meal is over, you’ll take pleasure in knowing that cleanup is much easier than you think.

Here are four tips to maximize the energy efficiency of your electric stove.

Consider cookware size. The pots and pans you use should have approximately the same diameter as the cooking zone. That way you ensure no energy is wasted.

Think about material. Stainless steel cookware and electric cooktops are the perfect duo, while vessels made with copper or aluminum bases can leave a residue that can burn onto the surface. Glass or ceramic cookware is not recommended because of its poor conduction and the potential to scratch the cooktop. No matter the material, use pots with lids when possible to better contain heat inside the cookware.

Choose the right shape. Use pots and pans that are very flat or have slightly concave bases at room temperature — they will become flush with the cooking surface when they heat and expand, which allows for good heat distribution.

Keep it clean. Dirty cooking zones can reduce the effectiveness of the stove. Because glass-ceramic cooktops are flat and non-porous, cleaning is effortless as long as you follow the right technique. Remove burned-on food with a metal scraper, perform a thorough cleaning with a certified cooktop cleaner and paper towel, and finish with a wet paper towel and wipe dry. Do not use ammonia-based and abrasive chemical cleaners, and don’t clean the cooktop while it’s hot. You should remove food that can attack the glass-ceramic, like sugar or jam, while the surface is still hot to prevent an interaction.

The evolution of the electric cooktop over the past century has made it a highly energy-efficient cooking tool. With a stronger understanding of how it works, you’ll be able to better control the heat and more efficiently prepare a delicious meal.

Stay tuned for the next installment of the How It Works series.

(12 Posts)

Hello, I’m Ted Wegert, Director Applications Engineering at SCHOTT North America. I specialize in product and material development and design, and mechanical analyses for glass and glass-ceramics. I’ve worked for SCHOTT for more than 18 years, leading product development for appliances, fireplaces, armor, and other industry applications. I’m an active member of the Association of Home Appliance Members, UL Environment, and the American Ceramic Society. I earned my bachelor’s degree from The Ohio State University. When I’m not working, I enjoy mountain biking, cyclocross, reading, and forming glass art. I’m also a frequent home renovator.

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