The paper describes experiments to investigate the feasibility of using electrical tomography for early characterisation of physical stability in selected products. The Manchester LCT tomograph has been applied to an 8-plane sensor hosted in a 1-l vessel. Measurements have been taken over periods up to 76 h. Tomographic measurements and reconstructed images are consistent with visual observations associated with experiments that readily generate a distinct visible 'separated layer'. Observed diurnal excursions in the measured voltages have been investigated and related to changes in temperature. Later experiments have been performed in a temperature controlled environment. Conductivity changes have been extracted from the reconstructed images for selected pixels. These reveal behaviour which is indicative of instability prior to visually discernible effects. (C) 2009 Elsevier B.V. All rights reserved.