The measurement and parameterization of biological impedance characteristics is a powerful tool to improve simulated studies in the field of electrical stimulation. Although the measurements are often performed ex vivo, the simulation results focus on in vivo applications. Denaturation by tissue death can alter its electrical properties. Preservation media are used to reduce structural degradation. In this work, we used electrical impedance spectroscopy to investigate the influence of different preservation media on the electrical properties of ex vivo liver. Samples were immersed or washed in saline solution, citrate buffer, and phosphate buffer to measure impedance spectroscopy. A control group with unwashed samples was also tested. We found statistically significant differences between washed and immersed groups. The electrical conductivity of untreated samples is significantly different from that of the literature. Also, the electrical permittivity was less affected but increased in all preservation media compared to the control samples. We advise washing the samples between electrical-related testing, as the conductivity is closer to the literature reports of in vivo impedance spectroscopy.