Why do some coffee bags use descriptions like nuts, chocolate, and caramel? Different chemical reactions during the coffee roasting process cause different perceptions of aromas, including something called sugar browning. Sugar browning ultimately alters how we perceive flavors and sweetness in our favorite cup of coffee.

What is sugar browning?

What’s browning in the world of coffee? Sugar browning is a classification of specific aromatic compounds found in roasted coffee, primarily categorized as nuts, chocolate, and caramel. Sugar browning occurs during two different chemical reactions that take place during the coffee roasting process; the Maillard reaction and caramelization.

Maillard Reaction

The Maillard reaction is one of the most complex chemical reactions to take place during roasting. During it, amino acids act as catalysts with reducing sugars, resulting in a non-enzymatic sugar browning process. It’s very similar to the chemical reaction that occurs when you brown a steak or chicken, for example.

The length and momentum of the Maillard reaction will affect sugar browning to determine the body and sweetness of the coffee, as well as the complexity of the sugar browning notes found within the final product. With the steak and chicken example, more depth and complexity are achieved when striving for that brown color.

As the length of the Maillard reaction extends, simpler flavors like nut turn into more complex flavor compounds like walnut or almond. Caramel increases in complexity compared to maple syrup or honey. Chocolate notes develop into dark chocolate or even vanilla.

TLDR; sugars and amino acids are reactive, resulting in the nonenzymatic browning of sugars present in the coffee, resulting in aromas.

Caramelization

Sugar browning continues within the roast as the oxidation of sugar begins under a high temperature, happening at the end of the Maillard reaction. The degree of browning and caramelization here is dependent on the temperature and end time of the roast.

Sugar browning notes achieved through caramelization are malt, nut, and browned butter. Caramelizing sugar actually reduces the sweetness of the end product, so it’s up to the roaster to decide how they’d like to feature the final product. Follow our coffee roasting tips to craft that perfect cup.

Flavor and aroma

Now that we know our favorite coffees don’t actually have chocolate in them, how do we taste those aromatic compounds? We perceive flavor and coffee taste profiles in a very complex ways. This is because your taste buds can only actually understand taste sensations like sweet, sour, bitter, salty, and umami.

The nose and olfactory system come into play when perceiving more specific aromas like chocolate. The olfactory bulb picks up the aromatic compounds present within the coffee and, together with the tongue, perceives flavor.