Coffee and Science: exploring the Origin and Coffee Flavor from a Chemical Perspective

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Where is your favorite coffee producing area? Brazil, Kenya, Ethiopia? Why do you care which country the coffee comes from? There is likely to be an important reason because the same variety of coffee has different chemical compositions depending on where it grows. These differences in chemical composition not only affect the flavor and appearance, but also help us better identify coffee.

Notes on the chemical composition of coffee. Photo Source: Nathan Colton

The relationship between region and chemical composition

Many factors affect the chemical composition of coffee. Producers control a large number of variables, including the varieties they grow, the time they harvest plants, and the way coffee is processed. They can also choose the environment in which coffee is grown, including how much fertilizer to use and the area of shade. The combination of these factors, as well as the natural environmental conditions of the area and specific plots, contribute to the unique flavor of each kind of coffee.

We have long distinguished the flavor of coffee according to its origin. We talk about fruit flavor, high acidity African coffee, or rich Central American coffee. Flavor is the result of the unique chemical composition of coffee, so we can conclude that the regional flavor is the result of the similar chemical composition of coffee in each region.

Coffee brewed in a Kalita filter cup. Photo Source: Miguel Regalado

Use chemical markers to identify coffee

Through nuclear magnetic resonance spectroscopy (better known as nuclear magnetic resonance fingerprint recognition), scientists have found that markers can be used to identify coffee from Colombia, and have used the same technique to identify robusta beans in blended coffee. This is an effective way to identify when you suspect that coffee blended with Arabica beans is mixed with cheaper robusta beans.

The researchers also studied phenols and methylxanthine compounds to identify coffee. These compound groups are found in all coffee.

Methylxanthines include caffeine, theobromine and theophylline. Phenolic compounds include organic acids and chlorogenic acids such as ferulic acid, quinic acid, caffeic acid, and compounds formed by a combination of quinic acid and caffeic acid called caffeoylquinic acid (CQA). Phenolic compounds produce most of the aroma and flavor of coffee.

It has been proved that these two groups of compounds are very sensitive to the changing environment of coffee plants. They are thought to be involved in the process of how coffee plants adapt to the environment.

Researchers from the European Health and Consumer Protection Commission classified coffee by origin by analyzing methylxanthine and phenolic compounds with an accuracy of at least 90%. Although impressive, the distribution of coffee on its continent is still too broad for practical application.

Coffee beans on the world map. Photo Source: Nathan Colton

Country-specific chemical composition

My own company, Sci-Fi Foods, specializes in identifying chemicals related to national or regional sources. We observed significant differences in the contents of caffeine and phenolic compounds (such as different CQA) in different coffees. For example, coffee from El Salvador and Venezuela contains very low caffeine and CQA, while Kenya's caffeine is known for its high CQA levels. Our research also shows that there are significant and characteristic differences in trigonelline and acetic acid levels in South American and Central American coffee.

We are working to find more consistent regional differences in coffee chemistry, with the goal of identifying producing areas by the concentration of key molecules. We hope that in the near future, we will be able to predict the source of unknown samples and distinguish raw coffee beans according to their origin.

Understanding the chemical composition and its effect on the profile may help to maintain or even strengthen the characteristics of each producing area. If we can better understand which factors affect the unique flavor of each region, we can try new conditions to strengthen or change the flavor characteristics.

Coffee, cherries and beans. Photo Source: Miguel Regalado

Why the relationship between the chemical composition of coffee and its origin is very important

It is important for bakers, buyers and consumers to understand how chemical components relate to raw beans and the flavor after baking. It can tell us what kind of beans we buy-if we know that compounds with high beans will produce the flavor we like, this may be a more accurate way to find our favorite beans rather than by understanding subjective flavor descriptions. A better understanding of chemistry can also help us develop methods of baking and cooking.

The relationship between chemistry and origin may have a similar impact, enabling producers to choose the varieties that best suit their farms and to influence the flavor of coffee through agricultural choices. For example, if they know that certain environmental conditions produce chemicals related to the desired flavor, they can choose to focus on creating that environment.

Coffee poured into a cup. Photo Source: Fernando Pocasangre

If we can identify the producing area by chemistry, we can register the coffee to protect the appellation of origin. Better identification can also improve transparency and ensure traceability throughout the supply chain.

Why is traceability important? Because the traditional coffee supply chain involves many participants, it is easy to forget where coffee comes from and what processes it has gone through. If we can use chemical analysis to identify origin and other factors, we can better trust the supply chain and increase accountability. This, in turn, can improve market access and may increase prices for small-scale premium coffee producers.

Chemical analysis may also help to reduce fraud and misrepresentation, such as the discovery of robusta beans in Arabica blended coffee.

Ripe coffee cherries on a coffee farm in El Salvador. Photo Source: Miguel Regalado

Obstacles encountered in further analysis of the chemical composition of coffee

In order to fully understand the relationship between the country of origin and the chemical composition of coffee, it is important to face up to a very important problem that there is not much chemical data about raw coffee beans stipulated by origin. Understanding the chemical composition of region-related coffee requires the analysis of a large number of coffee samples from each major coffee region during several harvest seasons.

Given that coffee is produced on several continents and in many producing countries, this is a daunting task for any research team or company. To carry out such a large-scale research, we need to make collective efforts.

More attention has been paid to the relationship between coffee chemistry and flavor. Various institutions, companies and enthusiasts have created a network to share data and ideas on the subject. This result is a systematic data record because more teams can learn from it which data points are still lacking. This should be an example of researchers who want to understand the link between coffee chemistry and origin.

A cup of coffee brewed with Ethiopian beans. Photo Source: Julio Guevara

Many benefits can be gained through a better understanding of the relationship between origin and chemical composition in raw coffee beans. The increased knowledge could inform agricultural practices, enable producers to choose the best varieties and better tailor methods to the region.

In addition to a better understanding of how coffee flavor is created, the analysis of chemical components can also help us improve the transparency and traceability of the supply chain.

If researchers and producers across the industry can collaborate and track data on a large scale, then there is greater potential for a more comprehensive understanding of coffee production.

Translated from Perfect Daily Grind