mr viet blog

How is Coffee Aroma
Created?

Why do we feel citrus, flower, berry, fruit, and many other notes in the coffee aroma? This article will give you answer to this question and explain how exactly is coffee aroma created.

What determines coffee aroma?

Any flavor is a volatile compound that stimulates our taste buds. There are the same compounds in coffee, but depending on the variety, processing, and growing conditions, they are formed in different quantities. These differences in the concentration of the compound are what make one coffee flavor different from another. For example, if we feel the aroma of an apple in coffee, there is a high concentration of compounds that are close to those which are in apple.

When the coffee is ripened, but not roasted, you can’t feel any aroma. In order for the aroma to open up, volatile compounds need to be revealed through a number of chemical reactions.

Annually, scientists discover more and more compounds in coffee, but it is already known that there are more than 1000 of them. There are those that affect the aroma the most. It makes no sense to provide their names as it doesn’t have any sense for people without a chemical education. Instead, let's learn about main groups of compounds and discover how they affect the aroma.

Furans – the predominant group of compounds found in coffee aromas. They give coffee a caramel flavor because they appear as a result of the melting and caramelization of sugars.

Pyrazines – the second largest group of compounds. They give cereal, walnut, or bread flavors to the coffee. Pyrazines have the lowest odor threshold, so they contribute a bit to aroma.

Pyrroles are the third group of compounds. They are responsible for the caramel, sweet, and baked notes in coffee.

The remaining groups are aldehydes, which create fruity and green aromas: herbaceous and floral. And guaiacol and related phenolic compounds give the aroma of coffee excessively acidic and smoky notes.

Why does the aroma of coffee change during roasting?

There are different processes that take place at each stage of roasting. Because of the formation of new substances, each process creates its own aroma.

Roasting process can be divided into several stages:

• Drying (up to 130 °C).
• Maillard reaction and Stecker degradation (from about 130 °C).
• Caramelization (from about 170 °C).
• Development time (crack to end of roast).
Compounds formed as a result of the Maillard reaction give notes of fried bread. Nutty and caramel notes are formed during the process of caramelization of sugars. Stecker degradation leads to the creation of fruity, sweet, ashy, and smoky notes in the coffee bean aroma.

Light roast coffee is more fruity because of the high amount of 5-hydroxymethylfurfural. During roasting process this compound is breaking down. Thus, there are fewer and fewer compounds that can create fruit flavor. Simultaneously with this, the amount of sulfur compounds increases, which contribute to the formation of a burnt aroma: ashy and smoky notes.

If you know what substances bring the aroma to coffee, you can understand what processes in the beans have already finished. Therefore, after roasting, cupping process is carried out. The roaster grinds the grain and brews it. Considering the aroma of the coffee, one understands if something needs to be changed. Those changes can be made in the roasting process in order to emphasize the descriptors.

How coffee aroma affects taste perception?

The coffee aroma significantly affects the perception of taste. For example, 2,3-butanedione, which has a caramel flavor, can enhance the sweetness in coffee. It's about sensory experience: when we smell caramel, we expect it to be sweet. The same can be expected from citrus: if we smell lemon, we expect acidity.

It happens due to fact that the receptors of the nasal mucosa "capture" the molecules of aromatic substances and send impulses to our brains. The brain forms expectations about the taste of the drink and creates the pleasure of anticipation.

That’s why the aroma of drink is so important. If there is an ashy-smoky smell from the cup, then it will spoil the impression before you taste it. And vice versa, a sweet smell will tune in to the sweetness in the drink.


Mr. Viet cooperates with Vietnamese farmers in Dalat region in order to connect them to the world coffee lovers. We carefully select and expertly roast different types of coffee that you can find in our online store. Our main desire is to share our love for such exotic and unique country as Vietnam with you! Contact us to try the real flavors of Vietnam and fall in love!
27.08.2021

Read more