The Maillard Reaction
The Maillard reaction begins at ~280°F (138°C), creating the browned crust on bread and meat.
The Science Summary
The Maillard reaction is a chemical process between amino acids and reducing sugars that produces hundreds of flavour compounds. It kicks off around 280°F (138°C) — well above the boiling point of water, which is why wet surfaces inhibit browning.
The Chemistry of Flavor
Named after French chemist Louis-Camille Maillard, who first described it in 1912, the Maillard reaction is arguably the most important chemical reaction in cooking. It is a form of non-enzymatic browning that occurs rapidly from around 280°F to 330°F (140°C to 165°C).
During the reaction, the reactive carbonyl group of a sugar interacts with the nucleophilic amino group of an amino acid. This initial reaction quickly cascades into a complex web of reactions, producing hundreds of different highly flavorful and aromatic molecules. These molecules are what give a seared steak its savory depth, roasted coffee its dark bitterness, and baked bread its irresistible crust.
The Enemy of Maillard: Water
One of the biggest mistakes home cooks make is trying to sear wet food. Because liquid water cannot exceed 212°F (100°C) at sea level, any moisture on the surface of your food will essentially steam it, pinning the surface temperature below the 280°F threshold required for the Maillard reaction to begin in earnest.
To achieve the best browning, thoroughly pat meat dry with paper towels before cooking, or even better, leave it uncovered in the refrigerator overnight. This allows the surface to dry out completely, meaning the pan's heat can immediately start the Maillard reaction instead of wasting energy boiling away surface water.
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