What is the Maillard reaction? It is one of the most important chemical reactions in cooking. That’s what it is! It is the difference between boiled steak and grilled steak, bread straight from the bag and bread that’s been toasted, steamed dumplings and pan-fried ones.
Specifically, the Maillard reaction is a chemical reaction between amino acids and a reducing sugar like glucose (reducing sugars are sugars that form aldehyde or ketone compounds in an alkaline solution). If your high school chemistry is a little rusty just know that hundreds of new compounds are formed during the reaction. Some of which supply color. Others supply flavor. I won’t list the compounds here, seeing as there are too many to list and they have names like: 6-acetyl-1,2,3,4-tetrahydropyridine (which, apart from acting as a tongue twister, is partly responsible for the flavor of many baked goods).
The reaction occurs between 140 to 165 °C (280 to 330 °F), though 310°F/154°C is the sweet spot where the reaction is most commonly noticed. The reaction requires high dry heat in cooking, though it can be coaxed along chemically for other purposes. It doesn’t occur in boiled foods because boiling water can never get hot enough. The types of amino acids and sugars present, the amount of water, and how alkali (alkali being the opposite of acidic) the food is all effects how the reaction occurs.
The Maillard reaction is named after the French chemist Louis Camille Maillard, who first described it during the 1910s. Note that the reaction is not to be confused with caramelization, which is another important browning reaction in cooking, but involves the breakdown of sugars at higher temperatures.
So, the next time you are chowing down on some golden-brown bread, some roasted chicken, or perfectly seared steak you now know what reaction helped make that food so delicious. Cooking is edible science.