Several non-aqueous electrolytes have been tested in the electroreflectance studies. We have proved experimentally that they give us good electroreflectance spectra compared with spectra of germanium single-crystals obtained both in aqueous and non-aqueous electrolytes. The described electrolytes may be used in the wavelength range of at least up to 6 µm. There has also been demonstrated the possibility of using non-aqueous electrolytes at low temperatures by studying the electroreflectance spectra of germanium at 210 K.