My favorite chocolate chip cookie recipe has a secret ingredient: brown butter. I chop a stick of butter into cubes and place them in a saucepan over low heat, and I wait. The process of browning butter can take some time, but the reward is fruitful: a rich flavor with a nutty aroma. I add the browned butter to the rest of my ingredients and scoop spoonfuls of dough onto my baking sheet. After nine minutes, the cookies are ready. They are gooey, chocolatey, and have that extra nutty something.
Browning butter by slowly adding heat over time is the result of a chemical fusion, a process that many people perform each day. It’s called the Maillard Reaction, coined by French chemist Louis-Camille Maillard in 1912, and it’s everywhere.
While browned butter might be the most obvious example, the Maillard Reaction occurs when steaks cook on a grill, as a loaf of bread turns brown in the oven and onions and garlic sautée in a skillet. Quite simply, this reaction results in richer, deeper flavors and aromas in our food after we have exposed it to heat.
Of course, it’s not that simple. I reached out to Dr. Joe Yeager, a chemistry lab instructor at Smith College since 2013, to get a better understanding of this cooking chemistry.
I walked into his office one morning as he was helping one of his students with chemistry questions. He was just as eager to answer my questions as he was to help his students complete a complex chemical equation. Dr. Yeager tailors his lab exercises to reflect real-world applications, such as environmental assessments and cooking concepts. He believes that everyone, not just his students, should have a basic understanding of chemistry, saying, “Chemistry is everywhere. Cooking, painting, gardening, working on your car. When you have an appreciation for chemistry, you notice more things in the world around you.”
I asked him if he knew about the Maillard Reaction. He told me that, in fact, it was perhaps his favorite chemical reaction because, “it is just so delicious.”
According to Dr. Yeager, this reaction can only occur when the food is subjected to a relatively high heat, above 248 degrees Fahrenheit. This is why the Maillard Reaction can never be achieved when boiling meat; water boils at 212 degrees Fahrenheit and could never be hot enough for browning to occur.
But what exactly is responsible for the crispy brown texture and mouth watering aromas? When food reaches the required heat, it releases reducing sugars, like fructose and glucose, as well as amino acids. These sugars and proteins fuse together to make entirely new flavors and smells. Each ingredient (onions, chicken breasts, bread dough) has its own unique combination of sugars and amino acids after being exposed to heat; Dr. Yeager says, “There are multiple pathways, a multiplication of routes, that lead to different desirable flavors and aromas.” The wide range of flavor avenues results in a plethora of tastes and aromas, so no two types of food taste quite the same after the Maillard Reaction.
He also noted that the Maillard Reaction works best in, “food given to offspring,” such as eggs, milk, nuts and seeds. These compounds contain the necessary building blocks for life, such as sugars and proteins, which allow for a greater range of flavors when exposed to heat.
I asked Dr. Yeager why he teaches the chemistry of cooking, and he responded that, “Everyone has a positive connection to food.” In the kitchen, we are chemists, experimenting with spices and flavors and pairings. Our aprons might as well be white lab coats, our stoves Bunsen burners.
The recent weather has encouraged to spend my time inside and bake all day. My kitchen fills with the wafting scents of nutty browned butter and soft chocolate chips. I offer cookies to friends, who happily oblige. They ask me what’s in the cookies — what makes them taste so good?
I shrug, and tell them it’s something I picked up from chemistry lab. They stare at me incredulously. I wink.
