An apparatus, method and system configured to produce and provide on-demand, immediate sequential dispensing of varying levels of carbonated water, such as carbonated water having a level of carbonation selected by an end-user, is disclosed. In one aspect, immediate sequential dispensing of varying levels of carbonated water is provided by varying the rate of agitation during a fixed agitation interval. The carbonating unit has a volume with an inlet in communication with a source of carbonating gas and noncarbonated water. An agitator is housed within the volume of the carbonating unit and is operated by a variable speed actuator.
