Readily available animal tissue such as ground beef is a convenient material for mimicking the dielectric properties of biological tissue when validating microwave imaging and sensing hardware and techniques. The reliable use of these materials depends on the accurate characterization of their properties. Tissue water content is a dominant factor in microwave frequency tissue properties, thus the effect of dehydration must be considered. The dependence of tissue properties on hydration is also important for new applications of microwave sensing for hydration monitoring.