A portable, self-contained beverage apparatus includes a container assembly having a known storage capacity for storing a consumable liquid, and a dispensing assembly disposed within the container assembly that dispenses variable, non-zero quantities of additives into the consumable liquid. The dispensing assembly includes multiple apertures structured and arranged to retain vessels containing the additives to be dispensed into the consumable liquid. The beverage apparatus also includes a level sensor disposed within the container assembly that determines a consumable liquid level of the consumable liquid stored in the container assembly. In certain embodiments, one or more positive displacement pumping mechanisms are configured to pump additive liquid from additive containers into a beverage chamber.