Simple instrumentation can evaluate wettability of cementing spacers and preflushes in a laboratory. With detailed knowledge of the apparent wettability of a solution, service companies and operators can more effectively choose surfactants required to displace nonaqueous drilling fluids and leave the casing water-wet. Water-wet casing allows cement to adhere more easily to the surface, reducing the potential for remedial zonal-isolation treatments. A new device that more precisely assesses wettability by measuring electrical activity in the test fluid during the water-wetting process removes subjective judgment from wettability analysis.