Grilled burgers have none of these advantages. Grills cook primarily through infrared heat — the electromagnetic radiation that travels from hot coals or grill bars the same way the sun’s heat energy travels through space — an altogether less-efficient form of heat transfer than direct conduction from a hot griddle. Browning and flavor development take longer, giving the patties more time to dry out. Rendered fat immediately drips off the burger and vaporizes in the fire below. That vaporization and the sooty deposits the fat subsequently leaves on the burger’s surface are essential to the flavor of char-grilled foods, but less trapped fat also means drier burgers.
There are structural issues as well. For thicker grilled burgers, I typically prefer beef that’s ground fresh and handled as minimally as possible in order to keep its texture light and tender. (Small air pockets in a loosely packed patty also act as insulators, keeping the burger’s interior a shade pinker as the exterior browns.) Try this with thin patties, though, and even those that survive the initial transfer to the grill will crumble when you try to flip them, falling through the grates like a smoky, fiery game of Kerplunk.
Solving this structural problem is straightforward. In many ways, ground meat resembles bread dough. Both of them get their structure through a matrix of interconnected proteins — animal protein in the case of ground meat, gluten in the case of dough — and rely on that structure to ensnare water, minerals, aromatic molecules and fat. We all know that the more bread dough is kneaded, the more robust this structure becomes. The same is true for ground beef.
Kneading the ground beef in a bowl will cause proteins to become entangled with one another: That’s bad news for big, fat burgers, but necessary for thinner burgers. I knead my beef until it forms a mass that’s just tacky enough to stick together. (Incidentally, do not be tempted to add salt to the meat during this kneading phase. Salt will dissolve some muscle proteins, causing them to link together excessively: Your burger patty will come out with the bouncy, smooth texture of breakfast sausage.)
This kneading introduces another problem: geometry. As a burger (or any bit of meat) cooks on the grill, several factors can alter its shape. Solid fat renders and drips out, water evaporates and flies off into the atmosphere, and proteins coagulate and contract. Any burger will lose girth as it cooks, but a thin, well-kneaded patty especially so. With loosely packed burgers, I aim for patties that are about an inch wider than the buns to account for shrinking during cooking. With thin patties, I had to practically double this pre-cooking overhang, and shaping a few ounces of ground meat into a patty with a half-foot diameter is no simple task!
