From steve51864:
Also, just learned:
They are basically divided into TWO categories:
1. Wood-aged Ports
Bottled and ready to be enjoyed; seldom improve once bottled. No need to decant, for they are filtered. Remain fresher after opening, even after 6 weeks.
2. Bottle-aged Ports
Unfiltered and spend only a short period of time in barrels; therefore, more robust and often fruitier than the filtered wood-aged Ports. Require decanting to remove the sediment. Once opened, drink within 4-5 days.
Wood-aged:
Ruby
Tawny
Colheita, (Tawny Ports, but from a single harvest. Aged in the barrel for at least 7 years with date of harvest and bottling given on the label.)
LBV
White Port
Bottle-aged:
Crusted Port, (new marketing invention; blend from a number of years and is bottled young with no filtration. Matured in bottle for at least 3 years before release. Good quality like a vintage port, but much cheaper.)
Bottle Matured LBV
Single Quinta Vintage Port
Vintage Port