Port is a sweet red wine with about 20% alcohol and rather low acidity and tannin. Ideally a good port should have a rich spicy flavor and in spite of its 20% alcohol, taste very smooth. Vintage style ports are very grapey. This grapiness comes from the practice of bottling these wines before they are 2 years old. Even though a vintage port is held in the bottle for a long time, it keeps its grapey flavor but in addition develops bottle bouquet, a special quality found only in bottle aged wines. It can take many years for vintage ports to become smooth if they have some tannin when they are bottled.