Abstract: A method and apparatus for mixing liquids or liquids (9) with particles (8) without the aeration of the liquid. The liquid and/or particles (8) opposed in a vessel (2) having an upper end (4) and a lower end (5) and a containing wall (3) extending between the upper and lower ends. A mechanical rotating means (6) disposed adjacent the upper end (4) and submerged in the liquid (9) is used to induce a rotational flow directed radially outward from a central region of the vessel towards the containing wall (3) to establish a swirling flow. The flow is characterised by an outer annular region (11) of moderate rotational flow adjacent the containing wall (3) moving from the upper end (4) toward the lower end (5), an inward flow adjacent the lower end of the vessel (2) and an inner core (12) of rotational flow about the central region of the vessel (2).