Why does Montresor keep urging Fortunato to turn back in "The Cask of Amontillado"?

The is actually a ploy designed to appeal to Fortunato's pride. Whenever Montresor urges Fortunato to turn back, he also adds, "Besides, there is always Luchesi". Since Fortunato is so proud of his ability to judge fine wine, Montresor knows he will not allow Luchesi to judge the wine. In fact, Fortunato always adds, " Luchesi cannot tell Amontillado from sherry." So Montresor lures Fortunato farther and farther into his vaults using Fortunato's pride, not really the wine, to get him where he wants him to be.