Oil migration is an important process in the formation of fat bloom on chocolate-coated confectionery, leading to consumer rejection. However, the exact mechanisms behind this phenomenon are still not completely elucidated, which hampers the development of a mathematical simulation model. In this paper, a model based on a cellular automaton (CA) is proposed and parameterized using experimental data obtained from confectionery model systems. This CA-based model is shown to be able to describe the oil migration in an adequate manner and can therefore be used to calculate an effective diffusion coefficient. Further, the potential of a CA-based approach for the further investigation of the fat bloom mechanisms is demonstrated by means of a case study where capillary rise is incorporated in the CA-based model. (C) 2013 Elsevier Ltd. All rights reserved.