You know, scumble. It’s made from apples. Well… mainly apples…*
There’s a recipe out there for Butterbeer, and a Pan-Galactic Gargle Blaster, so why not scumble? Can anyone help?
*For the uninitiated: it’s a very, very, very strong alcoholic drink from Terry Pratchett’s Discworld series.
From my understanding of it, its mainly apple juice and sugar, allowed to ferment so that you have something resembling cider. Then you freeze it. The water seperates out, leaving you with something stronger than the original cider. You then freeze it again, so that more water seperates out, carrying on this process until the scumble can be used to clean tarnished spoons. 
Cider is capable of taking scale off of anything, if you aren’t careful. I’m sure that scumble is apples, various other fruits (magical or otherwise) and the odd rat that fell into the mash. Ferment it, distill it, and viola! 
As per Equal Rites, that’s actually applejack and is described as such. Triple-distilled wild mountain peach brandy is also described when Esk turns the beer into same. My WAG is that scumble is a conglomeration of all “humorous fermented apple juice drinks” and mountain dew/poitin/white lightning/kill-or-cure moonshine.