The Maillard Reaction

That golden crust on bread, the caramelized edges of a grilled burger, the roasted aroma of coffee — all products of the Maillard reaction. Above roughly 140 degrees Celsius (280 degrees Fahrenheit), amino acids and sugars in food react in a cascade that produces hundreds of new flavor and aroma compounds.

This is not caramelization, which involves only sugars. Maillard needs protein and sugar together, which is why plain sugar syrup never tastes like a seared steak. Moisture is the enemy: wet surfaces stay at 100 degrees Celsius because water soaks up the heat. Pat your steak dry, and the browning happens faster.