Does searing meat really seal in the juices?

No. Searing does not seal in juices — and we've known that for nearly a century. The idea comes from the German chemist Justus von Liebig, who proposed around 1850 that a hard-cooked crust forms a waterproof shell around meat. Kitchens loved the theory; the great chefs copied it into their books. But simple experiments in the 1930s already showed it was wrong, and every modern side-by-side test agrees: the crust leaks freely, and a steak sizzles from first contact to the plate. That sizzle is the sound of moisture escaping and vaporizing right through the supposed seal.

The crust is not a lid

A seared crust is dried-out, browned meat surface — not a weld. Water passes through it the whole time the meat cooks. When food writer J. Kenji López-Alt tested it, a roast seared first and then finished in the oven actually lost 1.68% more juice than an identical roast cooked the other way around. High heat drives moisture off; it cannot trap it. Juice loss tracks internal temperature: the hotter the inside of the meat gets, the more its fibers squeeze out, seal or no seal.

So why sear at all?

Flavor. Above roughly 300°F, the meat's surface undergoes the Maillard reaction — the browning chemistry in which proteins and sugars combine into hundreds of new roasty, savory compounds. That crust is the whole point of searing. It even makes meat *taste* juicier, because intense flavor makes your mouth water — a neat trick that helped the myth survive.

Engineering an actually juicy steak

Dry the surface before it hits the pan — wet meat steams at 212°F and never browns. Sear hot for the crust. Then protect juiciness where it's actually decided: pull the meat before the interior overshoots, and rest it a few minutes so the juices redistribute before you slice.