Julia Higgins for Whiskey Advocate:
Coffee roasters big and small are turning to whisky distillers for used barrels to age their beans. “When we tried aging them in barrels for the first time, I was shocked that the end result was so interesting and balanced,” says Vermont Artisan Coffee & Tea Co. founder Mané Alves. “I thought the whisky flavor would overwhelm the coffee, but it was wonderful. It had the nuances of the whisky but none of the alcohol.”
I've tried the Oak & Bond Scotch Whiskey Barrel Aged Coffee personally and what Mané Alves said above is correct: the flavor is distinct, but not overwhelming. You can definitely detect the whiskey flavor in the coffee, but it doesn't taste like whiskey-flavored alcohol.
There's a smokiness behind the coffee taste that makes it an ideal afternoon pick-me-up. I highly recommend trying it for yourself and I'll be checking out the other flavors and roasters available as well.