Elasticity of coffee beans: A novel approach to understanding the roasting process

Abstract

The influence of the roasting process on the mechanical and elastic properties of coffee has not been systematically investigated yet, although they change substantially. This is due to the initial drying of the beans under water release, the following structural changes at increasing temperature, the onset of chemical transformations and the release of gases and volatile ingredients. The resulting cellular structures determine the roasting result in a significant way. As measuring the elastic bean properties during roasting is easily and reproducibly possible, informative relationships to other roasting parameters can be established. It is thus possible to carry out an accompanying and up-to-date roasting control, which currently takes place via the color perception of the roasting master only. The measured values provide access to further information on changes in the internal bean structure and the processes during roasting.Elasticity measurements can therefore trace the roasting progress down to the depth of the beans, without being limited to the surface information of the color measurement as actually practiced.