One key: 20-25% fat.

Whichever style you cook, pay close attention to the cuts of beef used in the grind. The traditional hamburger is made of ground chuck steak, rich in both fat and flavor, in a ratio that ideally runs about 80 percent meat, 20 percent fat. Less fat leads to a drier hamburger. Avoid, the experts say, supermarket blends advertised with words like “lean.”

Too much fat, on the other hand, can lead to equally troubling issues, and a mess in both fact and flavor. “You get up around 30 percent fat,” Mr. Symon said, and there are risks. “Things happen,” he said. “Bad things. Shrinkage.” Home cooks should experiment, he said, with blends that contain from 20 to 25 percent fat.