Which of the following describes the typical changes coffee beans undergo during roasting?

• A. Color change, expansion, and moisture retention
• B. Color change, expansion, moisture loss, and chemical transformations
• C. Size reduction, bitterness development, and aroma loss
• D. Color change, density increase, and oil development

Answer: (B)

The correct choice highlights the fundamental transformations that coffee beans experience during the roasting process. Initially, coffee beans undergo a visible color change as they transition from green to various shades of brown due to the Maillard reaction and caramelization of sugars. This change in color is accompanied by the physical expansion of the beans as heat causes water vapor to escape and gases to form within the softening cellular structure.

Moisture loss is a significant aspect of roasting, as beans typically start with a moisture content of around 10-12%. During the roasting process, this moisture is expelled, which is critical for developing the desired flavor profile. The thermal and chemical transformations that occur during roasting not only affect the taste and aroma but also induce changes in the structure and composition of the beans. The complex interactions between sugars, acids, and proteins lead to the development of aromatic compounds and contribute to the overall flavor complexity that is characteristic of roasted coffee.

Understanding these transformations is essential for coffee roasters aiming to achieve specific flavor profiles and for those interested in the science behind coffee roasting.