Tio Pepe is a brand of Fino sherry made by Gonzalez Byass, a producer in Jerez de la Frontera, Spain. Tio Pepe was first made in the early 1840's by José Angel de la Pena, the uncle (Tio in Spanish) of Manuel Maria Gonzalez, the owner of the bodega that would be known as Gonzalez-Byass.
At the time, most sherry production was darker (oxidative rather than reductive) in style. Gonzalez shipped barrels of this new, drier sherry to his agent, Robert Byass, which proved to be a success. In 1849, Manuel named the sherry after his uncle, calling it Tio Pepe.
Tio Pepe is made from 100% Palomino grapes, aged in a solera for four years, and is categorized as Fino sherry. It is 15% alcohol, very pale yellow in color, and has the aroma of ripe cheese, roasted almonds, vinyl, and chalk. It is very dry (it in fact says Muy Seco on the label).