The Science: The notion of "sealing in the juices" was invented in the mid-19th century by German chemist Justus von Liebig, who suggested that heat formed a watertight shell on the meat. In the 1930s, scientists found that the crust wasn't, in fact, waterproof, and thus that seared steak is no juicier.
The Solution: Searing creates a Maillard reaction, in which proteins and sugars produce flavor. But a juicy medium rare comes from grilling room-temperature meat on high, flipping it once, and removing it when red juices show. Let the meat rest for a few minutes, and slice it across the grain.—J.N.