The thermal diffusivity (alpha) of idli barter was determined experimentally assuming infinite slab geometry under transient heat transfer conditions. The value alpha of batter determined using batch (1.38 x 10(-7) m(2) s(-1)) and continuous (1.1 x 10(-7) m(2) s(-1)) idli steaming units were compared with the value obtained using Riedel＇s equation (1.42 x 10(-7) m(2) s(-1)) and Martens equation (1.47 x 10(-7) m(2) s(-1)).