The body of a quality grill should be made of heavy-duty material such as stainless steel or aluminum. Both materials make the convection process necessary for grilling possible and also protect against rust.
A good rule of thumb: The more stainless steel you have, the more expensive the grill is. This is true for both the inside of the grill and the outside. When purchasing a grill with stainless steel parts, look for grade-304 stainless steel, which is composed of 18 percent chromium and 8 percent nickel austenitic alloy. This grade of stainless steel is more resistant to corrosion than grade-430 stainless steel, which is found on some grills. And just like with sinks, make sure to check the gauge of the stainless steel. Remember, the lower the gauge number, the better the quality.
"The gauge of stainless steel that customers should look for is 18 gauge or better," says Rich Kalsi, president of Capital Cooking, a manufacturer that specializes in high-end grills and other cooking appliances. "Anything thinner than 18 gauge will end up feeling tinny."
Your grill's grates can be made from porcelain enamel, cast iron or stainless steel. Some things you should consider when selecting grates are:
How well do they retain heat?
How easy are they to clean?
Solid cast-iron or stainless-steel grates are typically found on higher end grills. Both retain heat well and are resistant to chipping. However, both take a little more time to clean than other grates. Consult your grill manufacturer for the best cleaning methods.
Porcelain-coated steel grates are found on less expensive grills. The thinner the grates, the less heat they will retain, and cheaper porcelain coating will chip off easily. Mid-range and high-end grills have porcelain over cast-iron grates. Cast iron will retain heat well; however, the porcelain can chip if not cared for correctly.
A good grill comes with a one-year warranty, while the best grills on the market come with a 10-year warranty. High-end grills typically come with a lifetime burner warranty as well.