In truth, any one of them can be enjoyed at any time of day, but, as with all things fancy, there's a proper time and place for each. Ruby port is a blend of different young ports bottled after about three years in the cask. Your palate should master ruby before moving on to more complex ports. With so much young wine present, ruby ports are spicy and unrefined, typically characterized by a berry taste.
Tawny ports are older than rubies.
They're aged in barrels, which causes the port's color to fade from dark purple to a more subdued maroon. Your next step up the connoisseur's ladder is vintage port, of which the U.S. is the world's biggest consumer. The 60,000-65,000 cases of vintage consumed each year by Americans easily surpass the volume downed in Great Britain. A blend of the best wines from a particular harvest, vintage port is barreled for about two years, then bottled and stored for several more, where it ages further. Deep in color and full in body, vintage ports offer far more complexity than ruby or tawny ports and should be decanted 24 hours before consumption for maximum enjoyment.