There are actually a wide variety of fortified wines in the world, for which Port is just one kind. But it is a special one, and of the fortified wines, it is the oldest. Fortifying means that a grape spirit, or brandy, is added to the wine to help preserve it. The brandy is added during fermentation, which then kills the yeast as the yeast can only survive in an environment that is just so high in alcohol. This means that wine retains its sweetness. From here, the wine goes into a series of ageing containers. Depending on how long the ageing process is, the wine maker is making Ruby or Tawny port.