I waffled a lot as to whether this belongs on the Spirits board or Beer board, but technically...it's a cocktail, so here goes.
First of all, let me clarify my personal definition of a boilermaker. Both my father and I picked up the habit while attending Purdue for grad school (albeit 20 years apart). To me, it is a beer and a shot, sipped side-by-side - no downing a shot with a beer chaser, no dropping the shot into the beer. I like to taste my booze, and I like good beer. And I like to enjoy them slowly while I watch football. So here is my question:
Traditionally, we're talking beer and whiskey. But my dad at least believes the whiskey can occasionally be swapped out for other spirits - but he does seem to have an unspoken rule about them having some barrel on them.
I've done Irish iterations: Guinness, Harp, or better Irish beers with Bushmills, Jameson, or John L. Sullivan (depending on budget and/or what I have kicking around).
A good rye beer seems to cry out for any one of the many ryes I have in my bar (she is small, but she is well-stocked in this regard).
And, when I'm feeling nostalgic, it's my dad's classic after-work combo of a red lager and a shot of Evan Williams.
But what whiskey goes best with an IPA? East coast and west coast styles seem to have different demands. Do barrel-aged sours go best with rum? And where does tequila fit in? Am I the only person who ponders this? Probably.