There are three main styles of Port: White, Red and Tawny. White Port comes from white grapes, where Red and Tawny Ports are (mostly or entirely) from black grapes.
Done properly, Tawny is a result of aging in 500 litre old barrels (pipes) which allow for slow, oxidative development, hence their colour and flavour. Red ports (mostly known as Ruby, LBV, and Vintage) are genrally aged in larger vats (toneis or balseiros) which reduce oxidation through their volume, so the wines retain more of their punchy, red fruit.
Up in the Douro Superior, whilst Quinta do Vale Meao's reputation may be largely founded on their extraordinary table wines, the Olazabal family have a special place for port in their family history, as their's is a direct lineage to Dona Antonia Ferreira. They're now growing a wonderfully authentic range of Douro-aged port wines.