Strength of cof fee beans under static and dynamic loading

Abstract

Paper deals with experimental research on the crushing of cof f ee beans of diff erent kinds under quasi-static and dynamic compression. The process of the crushing is described in details. It has been shown that there is variability in the crushing strength values. A relation between crushing strength and the cof f ee grain shape is also studied. Roasted Arabica cof f ee (Cof f ea arabica) beans were used for analyses. Arabica cof f ees were produced in diff erent countries. All Arabica samples were submitted to a light roast. The detail analysis of the experimental data shows that there is no signifi cant relation between parameters describing the fracture behaviour of the grains and grain geometry. These parameters are also independent on the grain weight. Compression of the cof f ee grains leads to their crushing. The fracture force is diff erent for the diff erent kinds of the cof f ee. The same is fact valid also for the strain at the fracture and for the energy absorbed during the grain crushing. Dynamic loading leads to the increase in the fracture force of cof f ee grains in comparison with the quasi static loading.