Stopper assembly for a serving device configured to be positioned in a neck of a container, such as a bottle, wherein the stopper assembly comprises - a body element arranged to fit in the serving device; - a valve element mountable on the body element, wherein the body element extends substantially in a direction transverse to the valve element; and - a handling element that is connectable to the valve element and extending in a direction substantially transverse to the valve element at an opposite side of the body element, such that the valve element is arranged in between the handling element and the body element, wherein the valve element comprises an opening through which the handling element is connectable, characterized in that the stopper assembly is adjustable with respect to the serving device between a storage position in which the stopper assembly engages with the serving device to close off the serving device to prevent liquid from passing through, and a serving position in which the stopper assembly is moved with respect to the serving device to allow liquid to flow through the serving device wherein the valve element is adjustable between an open position allowing air to pass through the valve element and a closed position in which the valve element sealingly engages with the body element for preventing air to pass through, such that when the valve element is in the closed position, and the stopper assembly is in the storage position, air can be sucked out of the container by means of a vacuum pump that cooperates with the valve element to obtain a reduced pressure in the container with respect to the environmental pressure for vacuuming of the container - a body element arranged to fit in the serving device; - a valve element mountable on the body element, wherein the body element extends substantially in a direction transverse to the valve element; and - a handling element that is connectable to the valve element and extending in a direction substantially transverse to the valve element at an opposite side of the body element, such that the valve element is arranged in between the handling element and the body element, wherein the valve element comprises an opening through which the handling element is connectable, characterized in that the stopper assembly is adjustable with respect to the serving device between a storage position in which the stopper assembly engages with the serving device to close off the serving device to prevent liquid from passing through, and a serving position in which the stopper assembly is moved with respect to the serving device to allow liquid to flow through the serving device wherein the valve element is adjustable between an open position allowing air to pass through the valve element and a closed position in which the valve element sealingly engages with the body element for preventing air to pass through, such that when the valve element is in the closed position, and the stopper assembly is in the storage position, air can be sucked out of the container by means of a vacuum pump that cooperates with the valve element to obtain a reduced pressure in the container with respect to the environmental pressure for vacuuming of the container