A. Treat “Traditional” LBVs (Late Bottles Vintage Port) such as those from Warre’s and Smith Woodhouse as if they were true Vintage Port. Other LBVs are more like fancy Ruby Ports which don’t need to be decanted and can be kept stoppered on the bar (or even better in your temperature controlled wine ‘frige) for at least a couple of weeks.
For Vintage Ports, Traditional LBVs, and Crusted Ports (all wine intended to throw a sediment as they age in the bottle) that you don’t plan to drink in one evening, use the following procedure:
1) Gently decant them into a clean decanter or clean empty wine bottle. There are two types of decanters: those for aerating young wine and those for decanting older wines that would be damaged by aeration. If you use a decanter, use the kind for older wines. YOu do not want the decanted wine to have a large surface area.
2) Rinse the original bottle very thoroughly with cold water and thoroughly drain it.
3) With minimal splashing, return the decanted Port to its original bottle.
4) Pour the wine and then gas (with Private Preserve or other nitrogen and/or argon-based wine preservation gas) and stopper what is left in the bottle.
Or you can decant and then pour from and gas the decanter, as long as it has a stopper. Gassed and stoppered decanters can keep the Port as well as a gassed and stoppered bottle. Or, if you know you will drink half the bottle, you can fill (from the decanter) a half bottle and then gas and stopper it and save this half bottle for another day. As long as you gas the wine early and seal it, it will keep for at least a week. It will keep even better if you keep it in the refrigerator (but not in the door).
You can use these same techniques for decanting and preserving any bottle of wine. The key to success is to expose the wine to as little air as possible. Decant gently using a funnel that runs the wine down the side of the bottle rather than one that sprays the wine out. The truly concerned wine geek might gas the empty decanter before decanting to displace the air from the decanter to further diminish the effect of oxygen. It is best to use a decanter that will be filled into the narrow neck to minimize surface area where the wine can be in contact with air.
I’ve tried every other technique I have heard of to preserve opened wine. Gassing and refrigerating the wine is the way to go.