The present invention describes a rotating mixing/stirring device that includes a shaft (1) connectable to a rotational drive element, the rotating shaft (1) having sufficient length to accommodate at least one integral, substantially orthogonal blade or impeller (5). The blade or impeller (5) is driven to rotate by the rotating shaft (1) and thereby mix and stir any liquid in which the device is used. The blade or impeller (5) includes a plurality of apertures (6) arranged perpendicular to the rotating shaft (1) and these apertures are tapered.