What does the phrase “caviar to the general” mean and Where does it come from?

The phrase “caviar to the general” means something that is an acquired taste; something too racy or too unfamiliar to be acceptable to the general public.

The expression is from Shakespeare’s Hamlet, Act II, scene 2, in which Hamlet, speaking of a play, says,

“.. . it was never acted . . . the Play I remember pleased not the Million, ’twas Cauiarie to the Generall.”