One difference between sherry and port is that port begins as partially fermented red wine that's mixed with brandy that still has some grape sugars. When the red wine is added, the fermentation stops. Sherry is allowed to complete its fermentation. True port comes from Portugal, with the best quality from the Douro region. Sherry comes from Spain, with the best being from the area between Cadiz and Seville.
Port gets its name from the Portugese city of Oporto. The name "sherry" comes from the town of Jerez de la Frontera.
The dark color of port is added by treading red grapes and adding them to the barrel. People tread for hours thigh-deep in a trough, or lagar, full of grape skins and juice. Port is kept in oak barrels between three and 50 years before it's ready to be drunk. Port can be tawny, ruby or white.
Soleras are halls filled with barrels that hold categories of sherries. When they're poured into the barrels, more mature wine is drawn off for blending. The blending process is complex and strictly monitored. Sherries are categorized as fino, which is young sherry; amontillado, which is a softer, darker sherry; and oloroso, which is a type of cream sherry.