Oloroso sherry is a type of sherry made in the oxidative style. Once primary fermentation is complete, barrels of Palomino wine are graded by their aroma, delicacy, and fineness. The best barrels go into the Fino progam. Wines that are considered "lesser" are marked for the Oloroso program.
These barrels are fortified with brandy to 17% alcohol, then aged in the solera system for a long period of time. Without the protective scum of flor, the oxidation process happens, turning the sherry a rich walnut brown color. Some oloroso sherries are sweetened with arrope -- cooked down Pedro Ximinez grape must -- to become "Cream" sherries.
True oloroso sherries are dark in color, very dry, and have a rich, oxidative finish. They smell like dark woods, walnuts, and furniture shops. Their texture is rounded and softer than Finos, and they lack the yeasty, salty notes that are typical of those sherries.
Oloroso sherries are fairly resistant to oxidation. Once opened, they should be consumed within a few months. They are a natural pair with dried fruits, hard cheeses, and wild game.