This article addresses the characterization of dispersion and homogenization phenomena in stirred vessels through the analysis of dispersion curves that can be obtained experimentally by means of conductivity measurements. New insights on mixing conditions can be achieved from the analysis of the qualitative and asymptotic properties of tracer dispersion curves. The results obtained are interpreted in the context of the spectral approach to the advention-diffusion equation. It is shown that any flow model aimed at reproducing the experimentally determined dispersion curves must be at least two-dimensional. Convention-enhanced dispersion associated with the spectral structure of the advection-diffusion equation is addressed.