[T.G]

If you need to store the vermouth (or wine) for an extended period, just get a bottle of water, like arrowhead, sparklets, evian, etc... pour out the water, and, over the sink, pour the vermouth (or wine) into the bottle, put the cap on loosely, then start slowly crushing the bottle until the level of liquid is even with the top of the threads. Screw the cap back on and chuck it in the refrigerator. It will last much longer now that you have eliminated the air/oxygen space.