There is still much we need to understand about the compounds that affect the taste, aroma, and mouthfeel of coffee. It is said that there are thousands of compounds that influence coffee flavor. So far, what we have discussed is just the tip of the iceberg when it comes to the complexity of coffee beans.
Although people have been studying the sensory attributes of coffee for over a hundred years and have identified many compounds (but not all), there is still no large-scale research that fully links specific compounds to particular sensory traits in coffee. In addition, most existing studies focus on one type of coffee — a specific variety, processing method, or origin — so I cannot provide a comprehensive view or detailed list of chemicals and their corresponding flavor attributes. Even if such data existed, we have just learned that the core of flavor is multisensory integration; that is, flavor is formed by the combination of various sensory attributes. As for how compounds combine to create the flavor of coffee, we know very little.
That said, we do know that coffee flavor compounds are influenced by multiple factors, including genetics, origin, processing method, roasting, brewing, and how it is consumed. Let’s now take a comprehensive look at the factors that influence coffee flavor.
Another common coffee variety, Robusta, has a different chemical composition. Many specialty coffee professionals (at least in the West) have traditionally considered its chemical composition less ideal, with characteristics of harshness, bitterness, burnt flavor, and rubbery taste. From a chemical standpoint, Robusta beans have a higher caffeine content (which can make it taste more bitter), fewer lipids, and more chlorogenic acids (which can also contribute to bitterness and astringency).
Additionally, different coffee varieties have different genetic compositions. There are dozens of Arabica coffee bean varieties used in specialty coffee, and new hybrid varieties are continually being developed. You are likely to have seen these variety names on coffee packaging: Bourbon, Typica, Caturra, K7, Maragogipe, SL32, and others. You can think of the compounds in these varieties as raw materials—they are the starting point for flavor compounds, aroma compounds, and so on, which ultimately affect our sensory experience. The potential characteristics of this raw material depend on the coffee bean’s cultivation method, growing region, processing method, roasting technique, and brewing method. But genetics is the foundation. If a potential taste characteristic (flavor!) does not exist in the genetic code, it cannot be created in any later stage. However, you can damage the potential characteristic (flavor!) at any subsequent stage. You can also work to release the best characteristics at every stage. Because there are many factors that affect coffee flavor, it is difficult to generalize the flavors and characteristics of different coffee varieties.
