If you are lucky enough to be serving a port older than 40 years, decant it 30 minutes to an hour before serving. Briefly: Let the bottle stand upright 10 to 15 minutes if it's less than 40 years old, and up to 30 minutes if it's older.

Does Port need to be decanted?

Vintage Ports mature in bottle and should be decanted to remove the natural sediment deposited by the wine and to allow the aromas developed during ageing to express themselves. ... With the Port bottle vertical, remove the seal and wipe the top of the bottle clean. Ease the cork out gently.

How long does Port last in a decanter?

Spirits and madeira can be kept in a (stoppered) decanter virtually forever but port and even sherry tends to deteriorate after a week or sometimes less. Wine that has not been strengthened by alcohol is often worse (and occasionally, in the case of concentrated, tannic monsters, better) after 24 hours in a decanter.