What is the purpose of adding rum, whiskey, brandy, etc… to beer?
Should you be able to taste the hard stuff or should it blend well with the beer?
What are some beer recipes designed for each of the three: rum, whiskey and brandy?
I’ve used bourbon in an Imperial Porter to get the flavor of a barrel without the barrel. In my case it was a flavor addition.
Paul
I’ve soaked toasted wood cubes in Maker’s Mark to get a Bourbon Barrel effect as well. You can definitely taste the booze but it is a background note.
I haven’t seen them added alone, but it’s common to use for spice extracts
THIS^^^^^
Been considering a peaty scotch ale. I love Laphroaig 10 Year and have contemplated how to get that flavor into my beer.
It was even Denny’s recipe. 
Paul
I did this with a mead/braggot once using peated malt. Although it can be very easy to over do the peat flavor. I believe I used 1 lb in a 1/2 barrel batch. But you may want to take that down to 1/4 lb for 5 gallons and see how you like it.
I’ve also soaked some oak chips in bourbon, then introduced the chips into my secondary. However, I have never heard of or seen a recipe that calls for hard alcohol. Interesting concept, though!
I have done this as well. I usually soak the chips for a week or two in cheap bourbon and add it to the secondary. It works pretty well for me. You can adjust how much wood you get in the beer by how long you leave it on the wood chips.