Dielectric properties of mirin (sweet rice wine for seasoning) at the microwave frequency range of 3003000 MHz and temperature range of 5-70 degrees C were measured. The effects of temperature, frequency and liquid concentration on dielectric properties were investigated. Dielectric constant and loss factor were related to frequency by using the modified Cole-Cole equation. The important parameters such as relaxation wavelength, static dielectric constant and ionic conductivity were determined numerically under experimental conditions. It was concluded that the index of spread in the relaxation times depended on mirin concentration and it spread with increasing concentration. Penetration depth was calculated based on the collected dielectric properties data and it had a trough at mixture ratio (v/v) of 1:1 (original:water). The relationship between dielectric properties and temperature was determined at 915 MHz and 2450 MHz for commercial significance. (C) 2008 Elsevier Ltd. All rights reserved.