Hmmm...
In "The Library," Bookman asks Jerry for some instant coffee. Jerry says he doesn't have any; Bookman asks, "Who doesn't have instant coffee?" Jerry replies, "I don't." (Implying that he never has it, IMO.) Then Bookman's classic advice: "You buy a jar of Folger's crystals, you put it in the cupboard and you forget about it. Then later on when you need it, it's there, it lasts forever. It's freeze-dried. Freeze-dried crystals."
Later, in "The Contest," George snaps at Jerry, "All you have is instant coffee? Why don't you get some real coffee?" Jerry replies, "I don't keep real coffee in here, I get my coffee on the outside."
Seems like Jerry actually took Bookman's advice and got some Folger's.
-B.