One of the best things about Cork (and there are many!) is that you have a choice of two stouts that aren't Guinness.
Murphy's is brewed at the Lady's Well Brewery in Blackpool and Beamish and Crawford is brewed on the South Main Street, just across the road from An Spailpin Fanach, one of Cork's better pubs and a great place for folk music.
Both brews are delicious - but don't take my word for it, I'm a native! Do try them if you're in the city.