Abstract: The invention includes apparatus and method for inhibiting the hardening of a wetted concrete premix in a filled concrete mixer including providing a rotatable concrete mixer drum having a plurality of sealed apertures located throughout the entire length and circumference of the drum such that at least one of the apertures is located at or near the bottom of the drum at all points of rotation, and injecting a fluid under pressure through at least one aperture and into the drum when filled with a charge of wetted concrete premix to disperse the fluid throughout a portion of the charge adjacent to the aperture and up to the surface of the charge thereby inhibiting hardening.