A system for measuring the dielectric propel-ties of cereal grains from 1 to 350 MHz with a coaxial sample holder is presented. Several polar alcohols were used to calibrate and verify permittivity measurements obtained with a signal-flow graph model from the full two-part S-parameter measurements. At the lowest frequencies (1-25 MHz), where the phase measurements are less accurate, a lumped parameter model was used for the dielectric loss factor measurements. The system was calibrated with measurements on air and decanol and verified with measurements on octanol, hexanol, and pentanol. The standard error for the polar alcohols used for verification was 2.3% for the dielectric constant and 7.6% for the dielectric loss factor. Although measurements were taken on static samples, the sample holder is designed to accommodate flowing grain. Dielectric properties measurements at 25 degrees C were taken on four hard red winter wheat cultivars ranging in moisture content from about 9% to 21% with bulk densities varying from 0.66 to 0.83 g/cm(3). Most of the data agreed with measurements reported in the literature.