Two anaerobic filters, one mesophilic and one thermophilic, were operated with a starch-based feed at a series of organic loading rates. The results were analysed in two ways, with a modified Stover.Kincannon model and an empirical model based on the influent COD and the hydraulic retention time. Both models were applicable to both filters and the Stover.Kincannon model showed that the thermophilic filter had a maximum COD utilisation rate almost 15 times greater than the mesophilic filter. The Stover.Kincannon model was further modified to describe the methane yield. There was essentially, no difference in the maximum specific methane yields from the two filters. The results of analysing the experimental data with the empirical model showed that, although the model described the performance of both filters well, the value of the predicted final effluent COD was very sensitive to the value of the exponent associated with the influent COD.