Occassionnaly, I will marinade a steak or roast in beer for a few hours
before cooking it. It tenderizes the meat I find on the bad cuts of
beef.

I also brew beer and I've had a few batches that had a bit of an after
taste. I keg my beer in 5 gallon kegs and by adding 6 to 8 ounces of
Scotch in the keg, it would mellow out the off flavors.