The cask of Amontillado is a cask of sherry, a fortified wine associated with the Jerez region of southern Spain. In Poe’s story, Montresor uses the promised wine as bait to lure Fortunato into the underground catacombs during Carnival.
Amontillado is not a separate broad beverage category like brandy or port. It is a style of sherry that begins with biological aging under a layer of flor yeast and then develops further through oxidative aging. This gives it a character distinct from lighter fino sherry and darker, richer oloroso.
The drink’s name is central to the plot because Fortunato considers himself an expert in wine and is eager to judge the supposedly rare cask. Montresor repeatedly encourages his curiosity while leading him deeper into the damp vaults, where the wine becomes part of an elaborate revenge trap.
A common mix-up is calling Amontillado simply “wine” or confusing it with port. Although sherry is wine, “sherry” is the canonical answer to this question, while Amontillado identifies the specific style being sought.