While we can quite expertly distinguish between Grüner Veltliner and Muskateller, between Merlot and Zweigelt when it comes to wine, we are usually still quite naive when it comes to coffee. Just like wine, the world of coffee offers us a great wealth of different varieties.
Coffea arabica and Coffea canephora (commonly known as Robusta) are the two most important coffee species on the world market. The varieties derived from them exhibit specific regional characteristics depending on their origin, geographical location, terrain, and processing, similar to the different grape varieties in winemaking. C. arabica and C. canephora share a common history. A historical paradox: C. canephora is the older species and a "parent" of the Arabica genus, even though it was discovered later. C. canephora has been used by humans since the mid-19th century. The history of the use of Arabica plants, on the other hand, begins between 500 and 1000 AD.
Ethiopia and Yemen are home to the oldest Arabica varieties. Ethiopia is the cradle of Arabica. Many local varieties arose naturally over millennia in the Ethiopian rainforests (Wolisho, Kudumé, Dega, Yawan, to name just a few). Over time, people selected from this diversity of plants based on specific characteristics to create new varieties (Dilla, Geisha, etc.). Further new varieties arose naturally through the expansion of Arabica cultivation to other regions.
Yemen was the first country to which the Arabica coffee plant spread from Ethiopia. And Yemen is the source of three varieties that are the starting point for many of today's hybrids—naturally occurring or cultivated: Typica, Mocha, and Bourbon. These three very old varieties are less productive than newer hybrids. They are highly prized by coffee connoisseurs for their rich aromas, which is reflected in the price of these green coffees.
New varieties – whether naturally mutated or bred by humans – also have a long history. For example, a mutation in the Bourbon plant was observed in 1935 – named Caturra. This plant became the basis for many breeding programs aimed at high yields. While a Typica plant yields no more than 500 kilograms per hectare, Caturra can produce up to 1,500 kilograms.
Nature and humanity are constantly striving to produce new varieties. Quality and yield represent the extremes of this pursuit. For a long time, humans focused on yield. However, these varieties have never been able to compete with the three oldest varieties in terms of taste.
Generally speaking, Arabica varieties have a higher acidity and more subtle aromas. Robusta varieties tend to be known for their tart, strong, smoky, and bitter-walnutty characteristics. The qualities of both are often combined in blends to create well-rounded, full-bodied flavor profiles. In plant breeding, there are also attempts to cross Arabica and Robusta varieties with the aim of combining the sensory attributes of Arabica with the resilience of Robusta.
Looking at both types of coffee at a chemical level reveals distinct flavor profiles. Significant distinguishing features include caffeine and chlorogenic acid content, fat and free amino acid content, sucrose, and polysaccharide content. As "molecular building blocks," these groups of substances play a major role in the roasting process and thus in the taste of the coffee in the cup.