Why do you need to match your cookware to the burner size? I received a great question recently about the standard recommendation stating your pan size should match the burner or heater size of the cooktop.
“HI, I just bought new double oven range with the ceramic top. It has a ” bowtie ” between two burners. Measures top to bottom burner 17 1/2” and 7″ side to side. Because of the bowtie I would like to use a griddle, but the Manufacturer say’s you should never go beyond 1 inch of the burners. If I do, what could happen to my stovetop(crack)? I saw griddle that measures 21 by 12 inches. The overlap is there. Can I use this griddle safely with out worries of my ceramic stove top? Thank you!”
First off, no worries about cracking cooktops with a mismatch, at least not right away. Let’s look at the way the burner and pan orient themselves in my simple sketch below.
If you look at the cross-section of the pan on the glass, over the heating element, you see how the pan is perfectly flat and rests evenly on the glass! This is great…but not always reality. Perfectly flat allows for full contact of the hot glass and the cookware. For a radiant cooktop, this is important as a good percentage of the heat transfer is by conduction (contact) from the hot glass to the pan. For induction, this is not so critical.
A full contact surface between the pan and the glass does two things. First, what your are cooking heats faster! Second, the heat leaving the glass to go into the pan keeps the ceramic glass panel cooler. (by cool, I mean below 1,100ºF /600ºC). This is the temperature the ceramic glass can begin to age and then eventually crack.
Here is a picture of a poor contact surface between pan and glass-ceramic. You can see the “too large pan” has contact points outside the heater perimeter below. So, the fast heat transfer via conduction is not there and the ceramic glass just keeps getting hot. If the thermal limiter below the glass catches the high temperature, it will cycle it off and on more often. This makes cooking slower you frustrated. The limiter is only in one place under the glass, so it’s probably not catching the hottest spot, and in those areas, the glass can age more quickly leading to an eventual break.
Unless the cookware is really warped and uneven, this process will take quite a bit of time to age the glass. The immediate problem is the poor cooking speed!
Obviously with a bowtie type heater, cookware is seldom a direct match. Just be sure to look for cookware that is really flat. Some cheaper cookware will actually bend when it gets hot. Best is higher quality cookware with a very slight concave surface. As this material gets hotter it will bow to flat.
So if your cookware doesn’t match in size, at least make sure it’s flat.
Keep in mind, the pan (and your food) will not be evenly heated in this scenario…but you probably already figured that out.
Hope this helps!