Why does fortunate want the other man to drink when montresor offers wime in the book the cask of amontilladi?

Fortunato wants the other man to drink because he believes he has a good palate for wine and wants to show off his expertise. Additionally, Fortunato may want to prove that he is not affected by Montresor's insult that a rival wine connoisseur could tell the difference between Amontillado and sherry.