Enhancing experimentation and modeling of the impact of coffee particle size on the dynamic process of espresso extraction

Espresso extraction is a complex process governed by interconnected
physical phenomena, where coff ee particle size plays a critical role. This
dissertation systematically investigates how variations in particle size affect
the hydrodynamics and mass transfer processes within the packed
coff ee bed, using controlled experiments and mechanistic modeling. Key
fi ndings reveal that particle size distribution infl uences bed compression,
permeability, and extraction kinetics of key marker components. A series
of mathematical models were developed and validated to describe diffusion-
convection interactions, off ering predictive insights for optimizing
espresso quality and enabling consistent performance in fully automated
coff ee machines.