This paper presents experimental results concerning the solidification of a binary aqueous solution flowing along a cold surface. Forced convection in the liquid phase is assumed to dominate over possible natural convection effects at the interface and the influence of the initial solute concentration is analyzed. Solute rejection at the interface is shown to influence the equilibrium temperature at the solidification front and the time evolution of the solid phase. Comparison with the numerical solution of a simple thermal phase change model shows that the solidification dynamics is compatible with a porous structure of the solid phase (solid fraction about 0.90), accounting for dendritic structure at the microscale. (C) 2003 Elsevier Ltd. All rights reserved.