An Introduction to the Three Main Varieties of Coffee Beans and Does Chlorogenic Acid Affect Coffee Flavor?

FrontStreet Coffee - Introduction to Three Major Coffee Varieties and Chlorogenic Acid Components

1. Arabica

The origin of Arabica is the Abyssinian plateau in Ethiopia (now the Ethiopian plateau). Initially used mainly as medicine, it was cultivated for roasting and drinking in the 13th century. In the 16th century, it was introduced to Europe through the Arab regions and subsequently became a beverage loved by people worldwide. Among all coffees, Arabica accounts for 75%-80%, and its excellent flavor and aroma make it the only native variety that can be consumed directly. However, its resistance to drought, frost damage, and pests is extremely low, and it is particularly not resistant to coffee's nemesis - leaf rust disease.

Arabica coffee beans are mainly produced in South America (except for parts of Argentina and Brazil), Central America, Africa (Kenya, Ethiopia, and other East African countries), and Asia (including parts of Yemen, India, and Papua New Guinea).

2. Robusta

A leaf rust-resistant variety discovered in the Congo, Africa, which has stronger disease resistance than Arabica. The hot and humid regions unsuitable for Arabica coffee growth are precisely where Robusta coffee thrives. Robusta has a unique aroma and bitterness; even just 2%-3% in a coffee blend can dominate the entire cup's flavor. Its taste is so distinctive and strong that direct consumption requires careful consideration. It is generally used in industrial coffee production such as instant coffee, canned coffee, and liquid coffee. Its caffeine content is about 3.2%, much higher than Arabica's 1.5%.

The main producing countries are Indonesia, Vietnam, and West African countries centered around Côte d'Ivoire, Algeria, and Angola. In recent years, Vietnam has been dedicated to becoming one of the major coffee-producing nations.

3. Liberica

West Africa is the origin of Liberica coffee. It has strong adaptability to various environments, whether high or low temperatures, humid or dry, but it is not resistant to leaf rust disease. Since its flavor is inferior to Arabica, it is only traded domestically in some West African countries (Libya, Côte d'Ivoire, etc.) or cultivated for research purposes.

According to ICO (International Coffee Organization) statistics, excluding domestic transactions in coffee-producing countries, about 65% of coffee circulating in the world market is Arabica, while 35% is Robusta. Arabica beans are characterized by slender and flat shapes, while Robusta beans are more rounded, making them easily distinguishable by appearance.

Chlorogenic Acid

Chlorogenic acid is formed through esterification, dehydration, and condensation of quinic acid and caffeic acid. This is a reversible reaction. That is, chlorogenic acid can undergo hydrolysis when exposed to water, breaking down into quinic acid and caffeic acid. Since hydrolysis is an endothermic reaction, the heating process during roasting promotes the decomposition of chlorogenic acid.

When chlorogenic acid fully decomposes into caffeic acid and quinic acid, this process is the "hydrolysis reaction" mentioned by Mr. Taguchi in his "Complete Guide to Specialty Coffee," which results in the appearance of sour bitterness (quinic acid) and astringency (caffeic acid) in flavor.

In cases of insufficient moisture (low bean water content or overly rapid dehydration before first crack), when moisture inside the green beans is insufficient (free water is used up prematurely), chlorogenic acid cannot fully decompose into caffeic acid and quinic acid. In this situation, chlorogenic acid undergoes a "dehydration reaction," where the quinic acid portion of the chlorogenic acid molecule dehydrates to form chlorogenic lactone. According to Taguchi Mamoru, this creates a good bitterness (bitter with sweetness), producing a layered sensation where bitterness transforms to sweetness during tasting. The above descriptions mainly analyze the situations chlorogenic acid encounters from a chemical reaction and structural perspective. Different processing methods lead to different results in chlorogenic acid decomposition.

Knowledge Expansion

Caffeine content: Arabica contains 0.9%-1.4%; Canephora typically contains 2%, sometimes exceeding 3%.

In Summary

FrontStreet Coffee is a specialty coffee research center, happy to share coffee knowledge with everyone. Our sharing is completely unrestrained, aimed at helping more friends fall in love with coffee. We hold three low-discount coffee activities every month because FrontStreet Coffee wants to let more people enjoy the best coffee at the lowest possible price - this has been our mission for the past six years!

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