Hi,

A copy from Amana,

Ranges
What kind of cookware can I use on a glass smoothtop?

Amana does not endorse any particular cookware brand for use on a
smoothtop. We do not recommend using any glass, glass-ceramic,
enamel-porcelain coated, or cast iron cookware. Small imperfections on
the bottom of such cookware can scratch the smoothtop surface. While
the surface is not "scratch-proof", it is highly scratch and impact
resistant. With proper cooking utensils and care, it will continue
looking good through years of use.

The cookware's bottom diameter should closely match the size of the
heating element or burner area for the best cooking efficiency. Pots
and pans that are too large (extending more than one inch over the
sides) may cause cooking times to increase. Pots and pans that are
much smaller will result in energy loss and could increase the
potential for accidents.

We recommend using heavy-gauge metal cookware that has a smooth, flat
bottom. The flatter the bottom surface, the better it will receive
heat from the element and conduct heat to the food. Cookware that is
warped or curved on the bottom will result in slow heat-up times and
may not even boil water. Many brands feature cookware with an aluminum
disk on the bottom, which makes good contact with the cooking surface.

To verify if a pan has an absolutely flat bottom, take a ruler with
you to the store when you shop. Follow these steps:
Place a ruler along the bottom of the pan.
Rotate the straight edge a full 360o around the bottom of the pan.
Check for flatness in all directions.
If you see light or a gap between the ruler and the pan bottom, the
pan will not cook efficiently

***********

A copy from Maytag,

Glass-ceramic cooking surfaces feature electric coil elements directly
under translucent glass. When the element is turned on, heat is
transmitted directly up (not sideways) to the pan. A red glow from the
coil element can be seen through the glass. The red glow will cycle on
and off as the element cycles to maintain the selected heat setting.

The elements of a glass-ceramic cooking surface will not respond to
changes in heat settings as quickly as conventional coil-type
elements. Start with a lower heat setting, then gradually increase the
setting until the optimum temperature is reached.

The glass-ceramic cooking area retains heat for a period of time after
the element has been turned off. Energy can be saved by turning off
the element early and finishing the cooking on the retained heat.

For safety reasons, there are "Hot Surface" lights on the cooktop to
remind users that one or more of the cooking areas is hot. The
light(s) will remain on until the area(s) is cool to touch.

It's a good idea to use special cookware on glass-ceramic cooking
surfaces. When the proper cookware is used, cooking times are
comparable to a conventional coil cooking surface. To achieve optimum
cooking performance, use heavy gauge, flat, smooth bottom, metal pans.

Correct Pan Flatness
Using flat bottoms is very important, heat transfers by conduction and
if the pan is not flat, heat is not transferred well.

Likewise, the surface has a protective built-in temperature limiter
which senses uneven heating. The element will cycle on and off when
uneven heating is detected and food will take longer to cook.

To determine if cookware is appropriate for use on a glass-ceramic
cooktop, try these simple tests:

Ruler Test
Place the edge of a ruler across the bottom of the pan.
There should not be any space between the ruler edge and the bottom of
the pan. Bubble Test
Put an inch of water into the pan. Place the pan on the cooktop and
turn the control to high.
As the water heats, observe the bubble formation. If the bubbles are
uniform across the bottom of the pan, it is suitable for a
glass-ceramic cooking surface.
Uneven bubble formation indicates poor pan/cooktop contact and hot
spots will result.
Correct Pan Size
Matching the size of the cookware to the cooking area is important for
even heating. Cookware should not extend more than 1-inch beyond the
indicated cooking zones.

Correct Pan Material
Consider the characteristics of the following pan materials:

Aluminum is an excellent heat conductor. Some food will cause it to
darken or pit. Anodizing improves stain resistance and hardness. Some
aluminum pans cause metal marks on glass-ceramic surfaces. These marks
need to be removed promptly to prevent damage. Brand names: Calphalon,
Magnalite Professional*.
Stainless Steel is a slow heat conductor if used by itself. It will
distribute heat very well if other metals (aluminum or copper) are
sandwiched between the stainless. Brand names: Jenn-Air, Revere
Pro-Line, All-Clad*.
Cast Iron is Slow to heat, but cooks very evenly once temperature is
reached. Heavy. Needs seasoning to make cleaning easier and to prevent
sticking and rusting. Must be very smooth, if used on glass-ceramic
cooking surfaces.
Porcelain-Enamel is a glass-like substance fused to metal. Heating
characteristics depend on base material (usually aluminum, stainless
steel, carbon steel or cast iron). Must be smooth. Brand name: Club
Supra, LeCreuset*.
Glass, Ceramic or Glass-Ceramic are slow heat conductors. Easy to
clean. Some types may only be used in the oven. Not recommended on
glass-ceramic cooktops.

jeff
Appliance Repair Aid
http://www.applianceaid.com/