Sherry is a Spanish fortified wine that is produced almost exclusively from the Palomino Fino grape. There are two basic types of Sherry, Fino and Oloroso, with all styles being variations thereof. The dividing line between the two can be largely attributed to one unique indigenous type of yeast known as flor. Flor grows spontaneously on the surface of wines in the Fino family while they are in barrel, and forms a layer that provides a barrier to oxidation. The resultant wines will retain a sense of freshness, and the flor will impart a distinctive set of aromas and flavors. It grows more evenly throughout the year in the cooler coastal towns and has a particular affinity for Sanlucar.

Those wines that do not develop flor belong to the Oloroso family, and are matured in contact with the outside air. This controlled method of oxidation results in darker, richer, mellower wines. After the vintage, experienced tasters evaluate the newly made white wines and classify them according to their expected development. This is the first step a young Sherry takes on its way to being bottled in one of a range of styles that are derived from the two basic types.