Spray drying is not solely a process for removing water; it is a particle formation process, the product of which will have certain properties and performance requirements. Control and manipulation of the created particle structure during spray drying is critical for the successful development of products with enhanced properties.

For this reason, the study of particle structure during drying has attracted significant interest along the years, focusing on predicting dried particle structure, properties and drying rate based on droplet drying history. In the case of drying above the boiling temperature, the estimation of final size, structure/morphology and density of the dried particle becomes even more challenging. This is because when the temperature of the particle rises above the boiling point, bubble nucleation, growth and collapse within the droplet can have a significant effect on the final structure and the drying rates of the droplets.

For these systems, only limited studies were reported and a deeper understanding of behaviour across a wide drying history, drop size, initial slurry concentration and material property space is still lacking. Therefore, this study aims to investigate the effect of boiling on the drying behaviour and the developing morphology with emphasis on the role of material properties.