What is warpage?
It's a natural property of metals that they will expand in all directions when heated. On a large piece of metal like the Flat Top, if some portion of the surface has a different temperature than the surrounding metal it will push against the cooler region as it expands and as a result the metal can push down or up causing deformation or "warpage". This difference in temperature can be caused by incorrect settings on the burners of a stove, the actual layout of the burners on a particular model of stove, or extreme temperature differences that can be caused by putting frozen food on the hot metal when cooking.
It's perfectly normal for there to be a small amount of warpage on the Flat Top when cooking, especially at higher temperatures. This can be seen as a slight curve across the width of the front of the Flat Top. The amount may vary depending on the type and style of the stove but will not affect the performance of the Flat Top. There is a small bend in the metal on the front lip designed to reinforce the Flat Top against this, but it's physically impossible to heat metal without it expanding and curving to a small degree. Once the metal cools it will return to its original shape.
This "bowing" will occur most often during the first few uses. Once the Flat Top has been heated and cooled multiple times the natural stretching and shrinking that occurs when the metal is heated will even out across the surface of the Flat Top, improving the overall flatness when cooking.
How can warpage be avoided?
Always use all available burners - Using just one or two burners to heat your Flat Top with can cause it to warp or buckle. If you're only cooking a small meal we still recommend turning all of the burners on or removing the Flat Top and using a skillet instead.
Pre-heat gently - Because the Flat Top is so large it can take time for it to heat evenly. Once it's up to temp it will stay there for a long time. We recommend starting with your stove set to low heat and gradually increasing the heat until you get to your target temp. It's actually easier to make it hotter once it's already warmed up, by pre-heating slowly you can control the heat more easily. To be efficient with your time you can start the pre-heating process while you're getting your ingredients together. It typically takes 10-15 minutes to completely pre-heat the Flat Top.
Start low and don't overheat! - You might get the urge to turn your burners up to full blast the first time you use the Flat Top, but don't! Most cooktops only need to be set to 1/3 to 1/2 power to heat the Flat Top to over 500 degrees. Our test stoves only need to be set to 3 out of 10 to reach 400 degrees for cooking. Most chefs agree that the maximum cooking temperature you'll ever need is 500-550 degrees for searing a steak. The Flat Top is designed to handle temperatures up to 600 degrees without damage. However, torture testing has shown that a regular electric coil stove set to full power can heat the Flat Top to an insane 900 degrees. Even the heavy duty Flat Top isn't designed to endure those temperatures without warping.
Don't use pots or pans - We do not recommend using pots or pans to heat water directly on the Flat Top for two reasons. First, it is far less efficient than placing the pot directly on top of the burner and will take much longer to bring the water to a boil. Second, the pot of water can act like a "heat sink" pulling a tremendous amount of heat from the Flat Top and possibly warping the steel temporarily.
Avoid wild temperature differences - It's perfectly fine to use "zones" of different temperatures on the Flat Top for cooking different kinds of foods at the same, but don't set them to extremes. For example, you wouldn't want o have one side of the Flat Top heated to 500 degrees for searing a steak while leaving the opposite side at 200 degrees. Also take care not to excessively pre-heat the Flat Top before adding a large amount of frozen foods to avoid extreme temperature changes.
Make sure the Flat Top fits your stove - The Flat Top is designed to fit standard 30" wide ranges. If you take a standard Flat Top and put it on a larger or smaller stove the burners will not uniformly heat the Flat Top and can damage it. We offer custom sizes that can fit just about any stove. If you're not sure that the standard Flat Top is right for your stove, send us a picture and we'll be happy to verify it for you.
What happens if I warp my Flat Top
There are two common ways that a Flat Top is warped: excessive heating or uneven heating caused by not using all of the burners on the stove. Below are the troubleshooting steps for each scenario
Excessive heating - Don't worry! In nearly all cases once the Flat Top fully cools it will return to normal. A small amount of "curve" is normal but it shouldn't be enough to rock on the stove. The Flat Top is designed to handle temperatures up to 600 degrees. It's very easy for stoves turned past medium to heat the Flat Top well beyond that. Use a thermometer to check the temperature of the Flat Top to find the correct settings on your stove.
Uneven heating - If you didn't use all of the available burners on your stove, for example turning on just one burner to cook a single egg, it's quite possible that the uneven heating warped your Flat Top. Normally, turning all of the burners on to medium low to let the entire Flat Top heat to around 400 degrees for 15-20 minutes will undo any damage. Once it cools it should return to flat.
If you think your Flat Top is doing something out of the ordinary reach out to us and we'll be happy to check it out.