Liquid transport and movement in yams were studied using an experimental system based on the analysis of charge couple device images taken during the capillary rise of a colored liquid in the yam. The generalized dynamic model of the liquid penetration into vertical cylindrical capillary used was based on the Lucas-Washburn equation. It had the advantage of independently characterizing the equivalent pore radius and the contact angle by determining the coefficient of diffusion of the liquid noted D and the height attained at equilibrium noted h(e). We studied cotton and viscose yarns and found that the diffusion of liquid and the height attained at equilibrium depending on the fiber type. These results were discussed on the basis of the wettability of the fibers. We used water and a chemical agent added to water to investigate the effect of the characteristics of liquid on the capillary rise in yams. The capillary parameters values (D and h(e)) depended on the concentration of the chemistry agent added to water. These results were discussed by studying the evolution of the characteristic of the porous media and the liquid properties by calculating the equivalent pore radius and the contact angle and measuring the surface tension and the viscosity of the fluid. (c) 2007 Wiley Periodicals, Inc.