How a small bean holds its own in the world

Wie sich eine kleine Bohne in der Welt behauptet

Coffee is a genus of plants in the Rubiaceae family. More than 100 species are known to date. The best-known of these are Coffea arabica and Coffea canephora (commonly known as Robusta). These are also the two most important coffee genera on the world market.

Looking at both coffee varieties 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 flavor of the cup. Caffeine remains essentially stable during roasting—its levels hardly change. Arabica beans typically contain around 1% caffeine, while Robusta beans contain around 2%. In its pure form, caffeine tastes bitter and contributes between 10% and 30% to the bitterness of the final cup.

To date, 72 different chlorogenic acids have been identified in green coffee beans. Their main groups contribute significantly to the characteristics of roasted coffee during roasting: Arabica contains up to 10% and Robusta up to 14% chlorogenic acids. Roasting can transform chlorogenic acids into spicy to smoky aromas like guaiacol, as well as vanillin. Other breakdown products—especially in darker roasts—such as chlorogenic acid lactones or phenylindanes, often cause extreme bitterness for the coffee drinker. These processes are therefore more likely and frequent in Robusta varieties. Here, great care in cultivation and roasting is essential to ensure that the gustatory advantages of this variety outweigh its disadvantages.

Besides their sensory effects, chlorogenic acids also make important physiological contributions – as antioxidants in the body. Coffee is considered one of the main food sources of chlorogenic acids. Caffeine and chlorogenic acids are so-called "defense metabolites" in coffee plants. Caffeine acts as a neurotoxin, primarily against herbivores. Chlorogenic acids have an antioxidant effect against stress reactions in the plant or serve as building blocks for lignin, which is essential for lignification. This means they help the plant defend itself against herbivores, infections, and inflammation. The more coffee varieties are forced to assert themselves in evolution, the more of these substances have been incorporated into the DNA blueprint. The name "Robusta" derives from this ability to withstand adverse conditions. Due to these properties, Robusta is gaining increasing importance in the context of climate change. New developments offer hope that its qualities will improve, and that in addition to its robust nature, we will also find a compelling taste surprise in our cups.