Graf. It was made up in a book by an author. Homebrewers thought it sounded good and made it.
http://darktower.wikia.com/wiki/Grafis a strong hard cider or apple-based beer widely consumed in In-World. The specifics of the beverage are not mentioned (except to say that some varieties of graf are weak while others are eye-wateringly strong).Modern homebrew aficionados have created a huge variety of graf recipes (usually calling it "graff"), originally inspired by the Dark Tower series (as there is no known historical beverage called 'graf'). They share in common the idea that graf is a malted, slightly hopped cider however many recipes also add a number of spices and/or adjunct fruits. Some recipes have a relatively small malt contribution (being almost entirely cider) while others could be described more as apple beer (with large amounts of malt and only a small amount of apple).Graf is said to taste tart, light and refreshing with a deceptively high alcohol content.
Stephen King invented a drink for his fantasy world, and people are making it based on the description.
Homebrewer "Brandon O" seems to have created the grandfather of the many variations that exist, now.
Hell, I'm not going to explain it. Here's a video.
A beverage that sounds amazing in a book, made by people, and now the idea has taken on a life of its own i the world, as people brew and create and it won't be long before someone is selling this stuff and making a living at it.
Is it any wonder operating on the boundaries of things, where speculation and life happens, is an addictive thing that makes me excited to get to work today.
Also, regarding the beverage of choice in the Dogsland novels, please do not anyone invent "Piss Gin" because I would really prefer not to be the person who gets blamed for that. (Khali would be neat, though.)