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Handbook

The Maillard reaction: where the crust comes from

The chemistry of the browned crust on meat and bread — and why it never happens in water.

The Maillard reaction is amino acids reacting with sugars under heat, creating hundreds of new aroma compounds and the brown colour. It is responsible for a steak's crust, a bread's crust, the taste of roasted coffee and dark beer.

What it needs
  • Surface temperature from about 140°C (active at 150-165°C). Boiling water tops out at 100°C — that is why boiled meat is grey, not browned.
  • A dry surface: moisture pins the temperature near 100°C until it evaporates. Pat the steak dry with a paper towel and the crust comes faster.
  • Not to be confused with caramelization: that one involves only sugars and starts higher (see the separate article).

Above ~180°C in a dry pan the reaction shifts into burning, with bitterness and acrylamide — past a certain point more heat makes both taste and health worse.