How long fortified wine lasts once opened

Fortified wines are the exception to everything said about opened bottles, and the reason is instructive: most of them have already been through the oxidation that ruins a table wine, so there is much less left for air to do.

The wines that keep are the oxidatively aged ones. Tawny Port, Oloroso, Madeira and Marsala will hold for weeks and in Madeira’s case months, losing definition slowly rather than falling over.

The wines that do not keep are the biologically aged ones, and this catches people out. Fino and Manzanilla are aged under a protective veil of flor precisely to keep air away from them, and once opened they behave like a delicate white wine: three or four days refrigerated, and noticeably worse after that. A bottle of Fino left on a shelf for a month is not the wine it was.

Vintage Port sits in between. It is a bottle-aged red with spirit in it, and once opened it will hold for several days to a week — longer than a table wine, far shorter than a Tawny.

For all of them, the same things help as with any wine: reseal, refrigerate, and use a smaller bottle if you have one.