abstract: This paper presents the results of investigations of the compressive strength, the strain, the modulus of elasticity and the specific work during uniaxial compression of core specimens between parallel flat plates. Mechanical properties were determined for grains wetted for different time, and dried in room conditions, as well as for grains dried in a microwave oven. Wetting caused inner damage of grain and decrease of the strength, the specific work and the modulus of elasticity by about 50%. Vitreous kernels were characterised by higher values of mechanical properties than mealy one. Microwave drying also caused inner damage of grain and resulted in the decrease of all mechanical properties.