This doesn't have anything to do with Harry Potter, but I was talking with someone recently about coffee addiction, and read a blog message on the same subject, and was reminded about what I think is one of the earliest comments about coffee in Torah literature.
Jewish law discusses the idea that it's improper to eat before morning prayers, because we should care about our relationship with G-d more than about our relationship with our stomach. Simple drinking, and according to some authorities light snacking, is OK, but having a real meal or any food or drink that we really invest time into is wrong.
The Jewish Law commentary Be'er Heitev (OC 89) quotes Pri Chadash as saying the following: "Coffee can be drunk (before prayer), particularly in Egypt where their thinking doesn't work properly without coffee." This certainly seems to legitimize my coffee addiction!
Interestingly, the Pri Chadash was written by Rabbi Chizkiya da Silva, who lived in Jerusalem roughly from 1659 to 1695. According to The World of Caffeine, the earliest records of coffee drinking were in the mid-1400's in Yemen, and the earliest written accounts are from the 1600's. So the Pri Chadash is old enough to be historically significant in the history of coffee.
It would be interesting to search more deeply for earlier discussions of the topic in Jewish literature.