Cooking for Geeks, 2nd Edition

310°F / 154°C: Maillard Reactions Become Noticeable

You can thank Maillard reactions for the nice golden-brown color and rich aromas of a Thanksgiving turkey, Fourth of July hamburger, and Sunday brunch toast. Coffee, cocoa, and roasted nuts all rely heavily on Maillard reaction byproducts for their flavors. If you’re still not able to conjure up the tastes brought about by Maillard reactions, take two slices of bread and toast them—one until just before it begins to turn brown, the second until it has a golden-brown color—and taste the difference.

The nutty, toasted, complex flavors generated by the Maillard reaction are created when amino acids in proteins and certain forms of sugars (called reducing sugars) combine and then break down. Named after the French chemist Louis Camille Maillard, who first described it in the 1910s, the Maillard reaction wasn’t well understood until the 1950s. During the reaction, compounds with free amino groups undergo a condensing reaction with reducing sugars. For example, meat has a reducing sugar, glucose (which is the primary sugar in muscle tissue), and also contains amino acids like lysine; with heat, these two compounds easily react with each other to form two new molecules.

The Maillard reaction is much more complicated than the other reactions we’ve talked about so far. One of the two new molecules generated at the start of the reaction is good ol’ H₂O, but the other is a complicated, unstable molecule that quickly cascades through more ...