The Maillard Reaction

MC / March 20, 2013

One of the most important flavor-producing reactions in cooking is the Maillard reaction. It is sometimes called the “browning reaction” in discussions of cooking, but that description is incomplete at best. Cooked meats, seafood, and other protein-laden foods that undergo the Maillard reaction do turn brown, but there are other reactions that also cause browning. The Maillard reaction creates brown pigments in cooked meat in a very specific way: by rearranging amino acids and certain simple sugars, which then arrange themselves in rings and collections of rings that reflect light in such a way as to give the meat a brown color.

The important thing about the Maillard reaction isn’t the color, it’s the flavors and aromas. Indeed, it 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. What begins as a simple reaction between amino acids and sugars quickly becomes very complicated: the molecules produced keep reacting in ever more complex ways that generate literally hundreds of various molecules. Most of these new molecules are produced in incredibly minute quantities, but that doesn’t mean they’re unimportant.

The Maillard reaction occurs in cooking of almost all kinds of foods, although the simple sugars and amino acids present produce distinctly different aromas. This is 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 — in other words, 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.

High-temperature cooking speeds up the Maillard reaction because heat both increases the rate of chemical reactions and accelerates the evaporation of water. As the food dries, the concentration of reactant compounds increases and the temperature climbs more rapidly.

caramelized carrots 4

Temperatures need to be high to bring about the Maillard reaction, but as long as the food is very wet, its temperature won’t climb above the boiling point of water. At atmospheric pressure, only high-heat cooking techniques can dry out the food enough to raise the temperature sufficiently. It’s not the water that stops the reaction, but rather the low boiling point at normal, sea-level pressure. In the sealed environment of a pressure cooker, the Maillard reaction can, and does, occur. This is something we exploit when making soups, like in our Caramelized Carrot Soup, or purees, like the broccoli puree in our Brassicas recipe. Adding baking soda to the pressure cooker raises the food’s pH (making it more alkaline), which also helps. Chinese cooks often marinate meat or seafood in mixtures containing egg white or baking soda just before stir-frying.

So, in boiled, poached, and steamed muscle foods, an entirely different set of aromas dominates the flavor. Drying and browning the surface first will, however, allow the reaction to proceed slowly at temperatures below the boiling point of water. This is why we sear frozen steak before cooking it in a low-temperature oven. Searing food before vacuum sealing and cooking sous vide can add depth to the flavor of sous vide dishes. This step should be avoided for lamb, other meats from grass-fed animals, and a few other foods in which presearing can trigger unwanted reactions that cause off-flavors and warmed-over flavors to form when the food is later cooked sous vide. We recommend searing those foods after cooking them sous vide.

Blowtorch-cropped

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, super-hot griddles and grills, and even blowtorches are also helpful tactics, such as when we deep-fry chicken wings.

You might think that raising the temperature even higher would enhance the Maillard reaction. It does up to a point, but above 180 °C / 355 °F a different set of reactions occur: pyrolysis, also known as burning. 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.

Adapted from Modernist Cuisine


110 Responses to “The Maillard Reaction”

  1. GrooTheWanderer

    For more on pH and the maillard reaction: The Kitchen as Laboratory by Cesar Vega et al. Chapter 13

    For a practical example: Simply slice an onion and divide between two pans. In addition to your oil or butter, add a pinch of banking soda to one pan.

  2. Not exactly typos – look closely. At each place where the author intended to put a dash for punctuation there isn’t one – there isn’t even a space. This is probably some sort of font incompatibility. Other than those instances, there isn’t a single misspelled word or grammatical error.

  3. Could you please explain why you say this…

    “This step should be avoided for lamb, other meats from grass-fed animals, and a few other foods in which presearing can trigger unwanted reactions that cause off-flavors and warmed-over flavors to form when the food is later cooked sous vide.”

    Thanks,

    Tim

    • We generally don’t recommend presearing lamb. The searing step destabilizes fatty-acids in the cell membranes of the muscle tissue in lamb, which can trigger a cascade of aroma-creating reactions that can lead to a mutton-like aroma during cooking, which is only great if you like mutton.

  4. […] One way to ensure proper cooking time is to quickly sauté or pan roast Brussels sprouts. We talked about the technique of pan roasting in the Barramundi recipe and it’s one of the Fluffys go-to tools for quick, easy, side dishes. In the case of sprouts or other sturdy veggies, pre-cooking is appropriate. Pre or par-cooking (blanching, steaming, or nuking) allows dense, coarse veggies to cook slightly (al dente) in the center before burning on the outside. Use the microwave, blanch or steam them, your choice. About 2-3 minutes in any method will get you to the hot pan of sizzling oil with just the correct amount of internal doneness. Cook them quickly, on super high heat, with healthy fats and a good measure of tasty garlic, salt and “peppah,” and the result is close to spiritual epiphany.  Enjoy the rewards of that magical Maillard effect! […]

  5. […] Beef stock, on the other hand, is a project unto itself, and not one I take on lightly. Good marrow bones are key, but they can be difficult to come by. Especially since he latest food craze, bone broth, has caused a run on them. Contrary to some of the recipes for “broth” out there though, I don’t like much in the way of extras added. No tomato paste, no onion peelings, no floating herbs. I want the essential ingredient, the core meat flavour to slide along your tongue, rush up your nose and pull the carnivore up through your body by the roots. Success depends on diligence and patience and deep faith–let’s call it reverence–in the maillard reaction. […]

  6. […] a “holy grail of all culinary chemical reactions,” according to a video, is when a Maillard reaction rearranges a amino acids and sugars in a flesh beef to furnish a quintessential browned tone and […]

  7. crissy

    Its a culinary article not an English essay lol

    great article btw , im studying culinary arts & i didn’t know there was an actual term for the browning or carmelizing process so thanx

    • kyle thomas

      Caramelization is an alternative kind of nonenzymatic browning. wikipedia.org/wiki/Maillard_reaction says “the reaction is a form of non-enzymatic browning which typically proceeds rapidly from around 140 to 165 °C (280 to 330 °F). At higher temperatures, caramelization and subsequently pyrolysis become more pronounced.”

  8. David Skender

    I have found your explanation about the browning process to be excitingly interesting ( very informative ). We have developed and patented our oven.In trying to get this unit to the marketplace I believe now that with this newfound explanation about the Maillard reaction you have made me realize that our hi-temp oven can be marketed like no other. Thank you, Dave Skender

  9. […] Once you have selected your cut of meat, you’ll want to make sure that you prepare the meat in a way that will ensure a superior end result. A dry steak gets a better crust. Water and moisture on the surface of the meat will first begin to steam when they hit a hot surface. Excess moisture will partially prevent the browning effect that a good hot sear will create (for more on this phenomenon, you can read up on the Maillard reaction). […]

  10. With due respect, meat without additions, does not appear to contain sufficient accessible sugars or glycogen to attribute meat browning primarily to Maillard reactions. This appears to be an oft repeated fable without much supporting evidence. I expect we are seeing fat+amino reactions rather than sugar+amino Maillard reactions, but that’s a guess.

  11. For those who don’t know, The Maillard reaction is a chemical reaction between an amino acid and a reducing sugar, usually requiring the addition of heat. Like caramelization, it is a form of non-enzymatic browning. It’s somehow similar to the effect you get when you sear food with a cooking torch after sous viding.

    Thank you Nathan for breaking down some myths in your intro. Love the information you put out on this blog

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