The objective of this study was to investigate the effect of particle surface moisture content on growth rate during fluidised bed agglomeration. In order to establish the relationship between process conditions and particle surface moisture content, the combined population balance and thermodynamic model, as described by Ronsse et al. (2007a,b), was used but was modified to include the degree of wetting and surface moisture content as variables in the population balance. Growth kinetics were experimentally verified by fluidised bed agglomeration tests using 100 mu m glass beads and maltodextrin based aqueous binder solutions, under varying process conditions. Studied process variables included binder concentration, fluidisation air temperature, liquid binder feed rate and liquid binder atomisation pressure. With the exception of varying binder concentrations, it was observed that a clear correlation existed between the model-predicted surface moisture content and the experimentally obtained growth rates. This work clearly demonstrates that, in population balance modelling of fluidised bed agglomeration, constant rate agglomeration kernels are insufficient and need to be sensitised to surface moisture content and binder concentration. (C) 2011 Elsevier Ltd. All rights reserved.