I'm just so taken with this story. I love rarepairs, and I particularly love rarepairs featuring the older and/or less traditionally-attractive characters like your wonderfully IC, curmudgeonly, appealing Aberforth. I like the believable dynamic you set up between Abe and Severus (his snarky comments are priceless and so IC) and the way you make Albus a full character despite his being totally offstage. And the clever ale premise -- love that.
Some lines I loved:
Each day in the Hog's Head was much like the last. It was one of the things Aberforth liked about it. Right from the start, Aberforth is so sharply characterized.
"Forgive me if I missed your display of gratitude," Severus snapped. "Your thanks must be lodged in my ears along with the snow." Great Snape line
Severus nodded. "Fate of the Wizarding World, he says. The usual." Beautifully-worded and so telling for all three of them.
Aberforth didn't need to look up to know when Severus came back. When most of your regulars preferred their heads covered and the barman's gaze not to linger on their face, you learned to recognise the particular tap and shuffle of each gait across the floorboards. It's details like this one that do so much to set the atmosphere and characters of this story.
He struck at serpent speed Yes, I see this. I love overall how characteristic the sex is -- nothing generic here.
"He'll be keeping you busy then," Aberforth said. "What with teaching, and saving the Wizarding World." Hahaha!
I could quote much more, of course, but you get the idea -- I'm impressed by this story. One of my fest favorites.