Maillard Reaction — The Science of Browning, Flavoring and Aroma

The reason behind mouth-watering crispy brown food

Fried and roasted food

If you have tried pan-frying chicken or fish for dinner, you must have noticed the beautiful browning on the exterior and the mouth-watering fragrances. This browning process can be seen in many different types of food, ranging from seared meat, pan-fried fish, roasted coffee and toasted marshmallows. Each of these foods have a distinct browning and a flavor which is the result of a special chemical reaction named Maillard Reaction. Let’s check out the science of browning, flavoring and aroma, without going deep in to the complex processes and jargon.

What is the Maillard Reaction?

Maillard reaction is the chemical reaction which occurs between amino acids and reducing sugars in the presence of heat that results the browning of food while forming new aromas and flavors.

Amino acids are the building blocks of proteins which can be found in our food. Reducing sugars are sugars which can act as reducing agents in biochemical processes.

Amino acids and reducing sugars found in food are rearranged in rings and groups of rings so that they reflect right in such a way that it gives the food the signature brown color as well as tons of rich flavors.

Brown crust of fried pork

The Maillard reaction is named after French chemist Louis-Camille Maillard, who first described it in year 1912.

The Flavor Reaction

The most interesting fact about the Maillard reaction is not the browning, but the aromas and flavors formed during the chemical process.

Although it is called the browning reaction, it is also called the flavor reaction as well. The molecules formed during this reaction are responsible for the characteristic smells which can be felt during frying, roasting, searing and baking. This process becomes complex when you leave the pan on heat for long. Proteins and sugars continue to react and form various, more complex molecules.

The Maillard reaction occurs in almost every food we cook. However, the aromas and flavors formed vary from food to food. Different sugars and proteins produce different aromas and flavors, depending on how you cook. This is why a porched egg will not taste the same as a fried egg. This is why you will not get the smell of frying meat in a pan, when boiling meat in a pot.

Fried egg

Temperature, Moisture and Time

Temperature, moisture and time are the key factors to get the Millard reaction started.

High temperature speeds up the Maillard reaction as it increases the rate of the chemical reaction and speeds up evaporation of water in the food. As food dries, the sugars and proteins become more concentrated, resulting in the speed up of the reaction. However, make sure your cooking temperature does not go beyond 180 °C / 355 °F. Going above this temperature will result in a different reaction named pyrolysis, which is commonly known as burning! People do like their food a bit charred, but too much charring and burning will result in bitterness, which is not that appealing to your taste buds.

If your food is wet, it will not reach a temperature 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. However, you can make the process happen at a lower temperature, with a lot more water. If you cook chicken or beef in vegetable stock for eight or 12 hours, still the result will be a brown, aromatic liquid. It is a rare chance that we will be cooking a single meal for that long. This is why we it will be a smart move to wrap your meat in paper towels and dry them before cooking. In order for your food to reach a high temperature during normal pan frying or searing, it is important to make sure that your food is dry.

Frying Meatballs

Proteins and Sugars

If there are no proteins or sugars, there will not be any Maillard browning and flavors.

Proteins and sugars are crucial for the Maillard reaction to occur. Some proteins are Maillard-susceptible. They love to react with sugars, but any type of sugar will not be a candidate. Complex sugars like starches and normal table sugar have large molecules and will not react with Maillard-susceptible proteins. Instead, simple sugars called reducing sugars can attract amino acids and react with them at certain temperature and moisture levels to start the Maillard reaction.

Juicy hamburger

Bottom line

If it wasn’t for Maillard, we would not have juicy seared steak, deep fried chicken wings, nor grilled sausages. All these browning, aromas and flavor bursts are a result of simple sugars reacting together with proteins. However, Maillard is not the only reaction occurring between these different molecules in food. For example, cake and steak contain the same building blocks, but cake contains more sugar whereas steak contains more proteins. When sugar heats and reacts with water, it results in caramelization.

Cooking is a science that has evolved with so much experimentation. It is this experimentation that taught us putting sugars and proteins together in heat, results in fantastic aromas and flavors.

The Maillard reaction does not just make food taste better. It has a science involved in it. Understanding the key facts allows you to manipulate the process of cooking according to what your taste buds crave for. It is the difference between blindly following a recipe and being able to make a recipe work for your taste.

Barbecue platter

Welcome to a place where words matter. On Medium, smart voices and original ideas take center stage - with no ads in sight. Watch
Follow all the topics you care about, and we’ll deliver the best stories for you to your homepage and inbox. Explore
Get unlimited access to the best stories on Medium — and support writers while you’re at it. Just $5/month. Upgrade

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store