Abstract: An apparatus is provided for determining the consistency of a cement slurry under varying temperature and time conditions. A liquid containing vessel includes a shaft extended from the bottom rotated by a motor supported exteriorally of the vessel. Within the vessel a cylindrical slurry cup is removeably supported for rotation by the shaft in an upright coaxial manner. Received within the slurry cup is a paddle having vertical portions in proximity to the interior wall of the slurry cup. The paddle has an upwardly extending coaxial shaft. Mounted in an opening in the top of the vessel is a potentiometer cup having a potentiometer in a plane perpendicular the shaft axis. A coiled spring also in a plane perpendicular the shaft has one end affixed to the paddle shaft and the other end secured to the potentiometer cup. A wiper arm extends from the shaft to the potentiometer.