The boiling of whole wheat grains was studied using magnetic resonance imaging (MRI) and pulsed-gradient-spin-echo nuclear magnetic resonance (NMR) (PGSE NMR). MRI was used to image moisture distributions across a central section of grains boiled for different times at either 100 or 120 degrees C. A moisture front gradually moved into the grain, although some moisture did penetrate ahead of the front. PGSE NMR, which measures self-diffusion indicated that two pools of water with differing diffusion characteristics may exist within the grain. Diffusion models suggested from the PGSE results were incorporated into finite-element simulations along with the Thomas-Windle model for diffusion/relaxation in polymers. Simulation results were compared to the MRI data, and the best fit was achieved using the Thomas-Windle model with a step-change in diffusivity above a critical moisture content. This behavior is similar to that of diffusion in polymers undergoing a glass transition, a phenomenon widely accepted to occur when starch gelatinizes.