So as many of you know, I sort of recently brewed an Irish Dark Mocha Stout. This was a 5 gal batch which was a basic stout recipe, but I added 4 oz cocoa nibs, 1/5th of Jameson Caskmates, and 4 cups of pressed Guatemalan dark roast coffee into secondary for 2 weeks.
At first the whiskey flavor was very pronounced and stood out very well, but after a few weeks the whiskey flavor has dropped out and has totally disappeared. One of my friends brewed a similar batch and the same thing happened. Anyone have a clue why this is occurring?