From America's Test Kitchen
Burgers often come off the grill tough, dry, and bulging in the middle. We wanted a moist and juicy burger, with a texture that is tender and cohesive, not dense and heavy. Just as important, we wanted a flavorful, deeply caramelized reddish brown crust with an even surface capable of holding as many condiments as we could pile on.
Ground chuck gave us the most robustly flavored burgers when pitted head to head against burgers made from other cuts of ground beef. We selected meat with a ratio of 20 percent fat to 80 percent lean; more fat than that, and the burgers were too greasy. Burgers made with less fat lacked in juiciness and moisture. We formed the meat into 6-ounce patties that were fairly thick, with a depression in the middle. Rounds of testing taught us that indenting the center of each burger ensured that the patties would come off the grill with an even thickness instead of puffed up like a tennis ball. Cooking the burgers over the fire for just a few minutes kept them tender, and lightly oiling the cooking grate prevented them from sticking.
Weighing the meat on a kitchen scale is the most accurate way to portion it. If you don’t own a scale, do your best to divide the meat evenly into quarters. Eighty percent lean ground chuck is our favorite for flavor, but 85 percent lean works, too. If you start with a chuck roast or steak, ask the butcher to grind it twice and expect some weight loss -- 2 to 3 percent in our experience -- to the grinder. Toasting the buns is an easy extra flourish; just split them open and lay the halves cut-side down on the grill rack for the last 45 to 60 seconds of the hamburgers’ cooking time.