Encouraging root-mean-square deviations from experiment of 0.024 g/cm 3 and 0.39 kcal/mol in ρ and ∆H vap were reported on a combined train/test set of 49 small organic molecules. With our automated methods for force field derivation and training, it appears that further accuracy gains can be expected by moving in future to polarisable and beyond-Lennard-Jones models.