Forgive me if this has been touched upon clearly and succinctly somewhere else. There is simply too much material for me to find a quick answer!
Without getting into my reasons for not adding these ingredients during the boil/primary/secondary, I wish to experiment on a per bottle basis by adding various amounts of flavor. I did this once with honey - straight to the bottle of a Pale Ale - and it worked out better than expected.
I have an Imperial Porter/Stout that's ready to be bottled and I was tossing around the idea of throwing some stuff in some of the bottles to experiment. Three things I was tempted to add (separately or in conjunction) were vanilla, coffee, and chocolate. If anyone has any experience doing so at the bottling level, could you share a tidbit of advice? I know, I know, bottling probably isn't the best way to impart these flavors, but I'm trying it out anyway.
Vanilla - will be using extract - I realize that I'll likely have to add vanilla to a larger volume of beer (in the bottling bucket) because it's so potent.
Coffee - I was thinking of throwing in a whole bean(s) into the bottle. Will this have any noticeable effect without crushing, etc.?
Chocolate - What form would you recommend? As always, I want a subtle, complex flavor here that won't overpower.
If it's even possible to add these things during bottling, I'd be psyched. If not, perhaps next time I'll play around at another stage of the game and get some flavors kicking.
Thanks very much in advance!