Abstract
The present work represents a basic investigation on instant coffee production by vacuum belt drying. A series of
drying experiments in a lab-scale dryer were performed varying the process parameters optimizing the product’s
properties. Density, structure and flavor of the product were tested and compared to commercial products, which
were produced by freeze or spray drying. It was found, that by optimized process parameters instant coffee can be
produced, which fulfills present product requirements. Furthermore, the mass transfer throughout the drying process
was analyzed, determining the effective diffusion coefficient by means of a thin film measurement technique.
Additionally the sorption behavior of instant coffee was systematically investigated and could be described using a
GAB sorption isotherm. No influence of the production process, coffee variety or temperature on the sorption
behavior was detected.