Editor’s note: This is the original recipe that appeared in Modernist Cuisine. For the recipe we adapted for Modernist Cuisine at Home, click here.
One of the most important flavor-producing reactions in cooking is the Maillard reaction. In discussions of cooking, it is sometimes called “the browning reaction,” but that description is incomplete at best. Indeed, it really ought to be called “the flavor reaction,” not “the browning reaction.”
To be sure, the Maillard reaction does create pigments that lend cooked food a tasty brown hue. It all starts with amino acids and certain simple sugars. Heat and chemistry rearrange those relatively simple compounds into new molecules of rings and collections of rings. The molecules produced keep reacting in increasingly complex ways that generate literally hundreds of new compounds. Some are pigments that turn the food an appealing brown color. But beyond these are a wide array of delectable flavor and aroma compounds. It is mainly the Maillard reaction we have to thank for the potent and characteristic smells of roasting, baking, and frying.
Pressure cookers are particularly suited for promoting the high temperatures needed to accelerate both the Maillard reaction and caramelization. These two processes are frequently mistaken for each other. They do go hand in hand in many practical situations, but they involve different chemical reactions. Whether you are caramelizing the food or “Maillardizing” it, you want to raise the temperature well above the boiling point of water to get these reactions going at a good clip. In a pressure cooker, the temperature of the steam can rise well above 100 °C / 212 °F.
adapted from the recipe for Caramelized Carrot Soup on page 3·301 of Modernist Cuisine