An experimental trial was carried out to evaluate, by means of determination of polar compounds and their subsequent HPSEC analysis, the influence of the hammer-crusher temperature during the olive paste preparation prior to oil extraction. Olives of Cima di Bitonto cultivar were processed utilising a laboratory-scale hammer-crusher conditioned at three different temperatures (12, 16 and 20 degreesC). The analytical results showed that the quality of the extracted oils was negatively influenced by increasing the crushing temperature. The oils obtained at higher crusher temperatures were more susceptible to oxidation than the oils obtained with crusher conditioned at lower temperatures. The HPSEC analysis of polar compounds was found to be useful to evaluate the oxidative and hydrolytic degradation levels of virgin olive oils also after slight thermal raising.