Cask of Merlot
The Cask of Merlot can be purchased for 8 15 from Roberto Pupellyverbos <Merlot Connoisseur> in Stormwind City. Pupellyverbos is in the Galina Winery in the Canals section of the city of Stormwind, on the perimeter of the Trade District.
As a quest objective
The subject of this section was removed from World of Warcraft in patch 4.0.3a but is present in Classic.