Williwig's Time Stopper

This magic bottle stopper's base is made of a mixture of cork and metal, but a stony, gargoyle figurine with a bored expression rests atop it. You can seal or unseal a bottle, flask, jar, waterskin, or similar container with the stopper as an action. When you do, the stopper magically resizes to fit the container's opening (up to 6 inches in diameter). While a container is stoppered in this way, any nonliving liquid inside it doesn't age, decay, rot, or spoil. If the container has a tap or similar means of dispensing the liquid without unstoppering it (such as a keg), the effect on the liquid ends once it leaves the vessel.