January 27th 2023

From bean to coffee

Students gain an exciting insight into the world of coffee

Recently, the students of the bachelor's degree program Biotechnology and Food Engineering had the opportunity to dive into the fascinating world of coffee as part of the elective "Sensory Science & Culinary Pleasure".

During the two-day seminar, students could not only gain theoretical knowledge about cultivation, harvesting and all process steps up to the finished coffee, but they also tasted, smelled and discussed the different coffee beans. Stefano Giannini from the Università del caffè, a competence center of the Italian coffee producer illy, held the interesting seminar.


The different stages of coffee seeds: on the left in the picture the closed seeds of the coffee cherry, in the middle a single seed (there are two of them in each cherry) with the so-called mucilage, on the right the green bean with the silver skin, which is removed only during roasting. ©Mohaupt

Arabica or Robusta? For the trained eye, it is easy to recognize that the one on the left in the picture is an Arabica bean. It is longer than the Robusta on the right and its center is curved in a sap-like S-shape. The Robusta bean is smaller, rounder and has an almost straight center. ©Mohaupt

Not all beans are the same. In this picture it becomes clear why the selection of the beans is so important. Different defects of the bean before roasting have an enormous influence on the taste and appearance of the bean after roasting. ©Mohaupt

The roasting is also decisive for the quality of the coffee. Depending on the degree of roasting, the coffee develops rather soft, low-acid or strong chocolate notes. The bean not only changes externally, the number of aroma components also increases from about 300 different aromas before roasting to about 1000 aromas after roasting. The changes in color and size caused by roasting are shown from left to right, with the green beans on the left and the beans after about 13 minutes of roasting on the right. ©Mohaupt

But the climatic conditions of the growing country are also of great importance for the taste and appearance of the bean. The bean on the left in the picture from Ethiopia and the one on the right from Guatemala are of the same origin, but clearly recognizable externally, yet different in color and luster. ©Mohaupt

All set for the course "Sensory Science & Culinary Pleasure". ©Mohaupt