I often hear people nattering on about carmelizing a steak, referring to the browning that happens when a steak is cooked at high heat. I’m usually in polite company, so I don’t often correct them…to Sheldonesque. But today I’m here to set the record straight.
One of the most important flavor-producing reactions in cooking is the Maillard reaction. Maillard Reaction is a term used to describe what happens when, under the influence of enough heat, sugars react with proteins and amino acids. When it occurs in food, it gives a flavor and color to foods. It occurs with simple sugars — fructose, lactose, and one form of glucose. One reason for dredging meat is that starches such as flour will break down in the presence of enough heat into simple sugars, providing material for a Maillard Reaction.
For it to occur, water cannot be present, because water lowers the highest temperature that is possible. That is why you will see chefs drying the surface of meat before they cook it. A Maillard Reaction starts at about 122°F but goes through 3 stages, with the final browning stage only kicking in at 309°F. Meat in boiling water won’t get hotter than the boiling point of water at 212° F which is why boiled or sous vide meat doesn’t brown. Oil will get hotter though than 309° F, which is why meat fried in oil will brown. A roast that you put in an oven still has water in inside it, but the surface of the meat loses its water through evaporation, enabling a Maillard Reaction to occur on the surface.
The important thing about the Maillard reaction isn’t the color, it’s the flavors and aromas. It probably should be called “the flavor reaction,” not the “browning reaction.” The molecules it produces provide the potent aromas responsible for the characteristic smells of roasting, baking, and frying. The Maillard reaction occurs in cooking of almost all kinds of foods, although the simple sugars and amino acids present produce distinctly different aromas. It’s why baking bread doesn’t smell like roasting meat or frying fish, even though all these foods depend on Maillard reactions for flavor. The Maillard reaction, or its absence, distinguishes the flavors of boiled, poached, or steamed foods from the flavors of the same foods that have been grilled, roasted, or otherwise cooked at temperatures high enough to dehydrate the surface rapidly(at temperatures above the boiling point of water). These two factors, dryness and temperature, are the key controls for the rate of the Maillard reaction.
One of the challenges to getting the Maillard reaction going is getting the surface hot and dry enough without overcooking the underlying flesh or at least overcooking it as little as possible. Cooks have developed several strategies to this end, some simple and some fairly baroque. One strategy that works well is to remove as much water from the surface of the meat as possible before cooking it (via blotting or drying at low temperature). Fast heating using deep fryers, superhot griddles and grills, and even blowtorches are also helpful tactics.
You might think that raising the temperature even higher would enhance the Maillard reaction. It does up to a point, but above 355 °F a different set of reactions occur: pyrolysis, also known as burning…and all of us have accomplished that. People typically like foods a little charred, but with too much pyrolysis comes bitterness. The black compounds that pyrolysis creates also may be carcinogenic, so go easy on charring your foods for visual appeal.
A Maillard Reaction is not the same as Caramelization. Caramelization is just sugar on its own breaking down, such as when you brown onions. A Maillard Reaction gives a more complex flavor than Caramelization, because more compounds are required for it to occur.
So there. You will never mix up The Maillard Reaction and Carmelization again. Spread the word.