What exactly is the Maillard reaction?

The Maillard reaction is a chemical reaction between amino acids (from proteins) and reducing sugars that occurs when food is heated above roughly 140 °C (285 °F). It produces hundreds of different flavour and aroma compounds and causes the characteristic brown colour of seared meat, toasted bread and roasted coffee. It is named after French chemist Louis-Camille Maillard, who first described it in 1912.

What is the difference between the Maillard reaction and caramelisation?

They are both browning reactions, but they are different processes. The Maillard reaction involves amino acids and sugars reacting together. Caramelisation is the pyrolysis (heat-induced breakdown) of sugars alone — no protein is needed. The Maillard reaction happens at lower temperatures and produces more complex savoury flavours; caramelisation produces sweet, nutty flavour. Serious Eats distinguishes the two clearly with examples.

What temperature does the Maillard reaction start?

The reaction begins at around 140–165 °C (285–330 °F). This is well above the boiling point of water (100 °C), which is why food that is wet or steaming does not brown effectively — the water keeps the surface temperature at 100 °C. A dry surface and high heat are both necessary. See the searing and browning guide for practical details.

Does the Maillard reaction happen in all cooked food?

It happens wherever high enough temperatures and the right chemistry combine — seared steak, roasted chicken skin, toasted bread, fried potatoes, roasted coffee beans, baked biscuits, and even dried pasta. It does not happen in foods that lack protein or reducing sugars, and it is slowed significantly by moisture. BBC Good Food explains why meat browns in accessible terms.

How do I get a better Maillard reaction when cooking at home?

Three things: dry the surface of food before cooking (pat meat dry with kitchen paper); use a hot pan — cast iron or stainless steel, preheated until a drop of water skips across the surface; and don't crowd the pan, as too much food drops the temperature and creates steam. Also, don't move food too early — let the crust form before flipping. See Serious Eats' Food Lab on searing steaks.

Maillard reaction — CookTheGuide Glossary

The chemistry, briefly

When food is heated above roughly 140 °C (285 °F), amino acids (from protein) and reducing sugars react together to form hundreds of new flavour, aroma and colour compounds. The result is the brown, savoury crust on a seared steak, the golden colour of baked bread, the depth of a roasted chicken, the bitterness of espresso. According to research indexed on ScienceDirect, more than 1,000 volatile compounds have been identified as products of the Maillard reaction — which is why browned food is so much more complex in flavour than food that is simply boiled or steamed.

Why water is the enemy of browning

Water boils at 100 °C — well below the 140 °C threshold the reaction needs. A wet surface cannot exceed 100 °C until all the moisture has evaporated. This is why patting meat dry before searing matters, and why crowding a pan (which creates steam) kills browning. It also explains why stewed meat stays pale and moist: the liquid holds the surface below the reaction temperature. Serious Eats covers this in detail.

Maillard vs caramelisation

Both produce browning, but they are distinct. Caramelisation is the heat-induced breakdown of sugars alone, with no protein involved. It produces sweet, nutty, slightly bitter flavours — think toffee or browned onions. The Maillard reaction requires both amino acids and sugars, and produces a far wider range of compounds with deeper savoury character. Many foods undergo both reactions simultaneously when cooked at high heat.

Where you see it in cooking

Seared steak, pork chops, chicken thighs
The crust of bread and pastry
Toasted bread, crumpets, waffles
Roasted vegetables — especially potatoes
Coffee beans during roasting
Biscuits, cookies, pie crust edges

The searing and browning guide shows how to apply the conditions for this reaction in a home pan.

Sources

Maillard reaction

The chemistry, briefly

Why water is the enemy of browning

Maillard vs caramelisation

Where you see it in cooking

Maillard reaction — common questions