Maillard Reaction
The chemical reaction between amino acids and reducing sugars that creates the brown, flavorful crust on seared steak.
The Maillard reaction is a cascade of chemical reactions between amino acids (from proteins) and reducing sugars that occurs at temperatures above approximately 280°F (140°C). Named after French chemist Louis-Camille Maillard (1912), it produces hundreds of flavor compounds, brown pigments (melanoidins), and aromatic molecules responsible for the complex savory character of seared meat.
The reaction proceeds in stages: an initial reaction between amino acids and sugars forms glycosylamines, which rearrange into Amadori compounds, which then undergo further degradation, dehydration, and recombination to produce the final flavor and color molecules.
Key flavor compounds produced: pyrazines (nutty, roasty), furanones (caramel-like), thiophenes (meaty, savory), and 2-methyl-3-furanthiol — one of the most potent "meaty" aroma compounds known, detectable at parts per trillion.
Temperature dependence: The reaction rate approximately doubles every 18°F. This means a 600°F pan surface produces Maillard browning roughly 16x faster than a 350°F surface. Speed matters because less time searing means less heat penetrating into the interior.
The moisture barrier: Water on the steak's surface caps temperature at 212°F (boiling point), preventing the 280°F+ needed for the Maillard reaction. Dry surfaces brown faster — this is why dry brining, patting dry, and the reverse sear's dehydrating oven phase all improve crust development.
Not caramelization: The Maillard reaction requires amino acids + sugars. Caramelization involves sugars alone. They're different chemistry. On steak, the Maillard reaction dominates.