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.
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.
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.