A beverage filtration device, comprising: an ion exchange resin-filled cartridge; a lid body having an internal housing configured to hold the ion exchange resin-filled cartridge therein, the lid body having a connection end and a top end having an opening therein; and a stem body, the stem body including: a cap region configured to couple to the connection end of the lid body to form a liquid-tight seal there-between, a collar, wherein a first portion of a wall of the collar is sized to fit inside a mouth of a beverage container and a second portion of the wall sized to be located outside of the mouth, a beverage conduit spanning the collar, wherein a first opening of the conduit opens to the coupling between the cap region, the conduit extends from the coupling between the cap region and the connection end, and a second opening of the conduit opens to and is located in an interior of the beverage container, and a stem body air tube extending through the collar, wherein: a proximal opening of the stem body air tube opens to an air vent hole located in the second portion of the wall of the collar, and a distal opening of the stem body air tube opens to the interior of the beverage container, wherein the second portion of the wall of the collar includes a housing that defines an air reservoir ending at the air vent hole, a length of the air reservoir being perpendicularly oriented relative to a length of the stem body air tube. an ion exchange resin-filled cartridge; a lid body having an internal housing configured to hold the ion exchange resin-filled cartridge therein, the lid body having a connection end and a top end having an opening therein; and a stem body, the stem body including: a cap region configured to couple to the connection end of the lid body to form a liquid-tight seal there-between, a collar, wherein a first portion of a wall of the collar is sized to fit inside a mouth of a beverage container and a second portion of the wall sized to be located outside of the mouth, a beverage conduit spanning the collar, wherein a first opening of the conduit opens to the coupling between the cap region, the conduit extends from the coupling between the cap region and the connection end, and a second opening of the conduit opens to and is located in an interior of the beverage container, and a stem body air tube extending through the collar, wherein: a proximal opening of the stem body air tube opens to an air vent hole located in the second portion of the wall of the collar, and a distal opening of the stem body air tube opens to the interior of the beverage container, wherein the second portion of the wall of the collar includes a housing that defines an air reservoir ending at the air vent hole, a length of the air reservoir being perpendicularly oriented relative to a length of the stem body air tube. a cap region configured to couple to the connection end of the lid body to form a liquid-tight seal there-between, a collar, wherein a first portion of a wall of the collar is sized to fit inside a mouth of a beverage container and a second portion of the wall sized to be located outside of the mouth, a beverage conduit spanning the collar, wherein a first opening of the conduit opens to the coupling between the cap region, the conduit extends from the coupling between the cap region and the connection end, and a second opening of the conduit opens to and is located in an interior of the beverage container, and a stem body air tube extending through the collar, wherein: a proximal opening of the stem body air tube opens to an air vent hole located in the second portion of the wall of the collar, and a distal opening of the stem body air tube opens to the interior of the beverage container, wherein the second portion of the wall of the collar includes a housing that defines an air reservoir ending at the air vent hole, a length of the air reservoir being perpendicularly oriented relative to a length of the stem body air tube. a proximal opening of the stem body air tube opens to an air vent hole located in the second portion of the wall of the collar, and a distal opening of the stem body air tube opens to the interior of the beverage container, wherein the second portion of the wall of the collar includes a housing that defines an air reservoir ending at the air vent hole, a length of the air reservoir being perpendicularly oriented relative to a length of the stem body air tube.