"Grill grates are only there to keep your meat from falling into the coals. The smaller and lighter the better."J. Kenji Lopez-Alt, author of The Food Lab, 2016 Cookbook of the Year
Which grill grate is best: stainless steel, cast iron, enamel coated, plated wire, or cast aluminum? The answer may surprise you.
Before we take a look at the different grill grates and consider their pros and cons, you really should read my article busting the myth of grill marks. It discusses how to get the perfect surface color on your meats, a rich, dark brown color from edge to edge with no tan in between. Essentially, no cross-hatched grill marks. That's max flavor, just as you can see on the surface of this grilled ribeye.
Yes, I know you've been indoctrinated all your life to start drooling when you see grill marks, but the truth is that grill marks mean much of the meat's potential has been lost. Tan meat is meat that has less flavor than brown meat. So the goal should be an even dark brown all across the surface.
When you buy a new grill, you might want to replace the grates to get the best browning on your meat. The conventional thinking on gridirons focuses on their ability to hold and transmit heat. That's why there is a mystique about cast iron grates. They absorb and hold a lot of heat, and they brand the meat surface with that heat, creating dark sear marks. But I don't want my grill grates to cook just parts of my meat. Grill marks mean that only about 1/3 of the surface has been altered by the magical Maillard reaction, the process by which tan, dull meat is transformed to a brown, intensely flavorful crust. I want the radiant heat of the fire below, accompanied by smoke and combustion gases, to do the job. If I wanted the metal itself to sear my steaks I could do it better in a frying pan. On a grill, I want an evenly-cooked surface, not black stripes on the surface.
Worse, thick cast iron grates with little space between them block smoke from contacting the meat surface. Smoke is one of the main reasons we cook outdoors, isn't it?
Think about the Brazilian steakhouse where everything is cooked on rotisserie. Waiters come to your table with the meat still on the spear and cut thin slices, not more than 1/4" thick from the surface of the meat. Then the meat goes back over the coals until the surface browns again. The whole purpose of the system is to give you an evenly browned surface with medium rare meat immediately below. The meat is delicious, and there isn't a grill mark in sight.
OK, sometimes grill marks do come in handy. When you are cooking thin or small foods like skirt steak, asparagus, kabobs or shrimp, it is almost impossible to get dark brown surfaces with just radiation or convection before the center is overcooked. The only thing that works is conduction. And that means grill grates that transmit heat well. That's why my two favorite grill grates are polar opposites. The best solution for both gas and charcoal grills? For gas grills, I recommend GrillGrates (TM), and for charcoal grills, thin stainless steel grates get the job done.
One last thing: When you get a new grate, fire up with the grate in place for about 30 minutes without food in order to burn off any grease, dust, or manufacturing byproducts. Your guests will thank you.