St. Patrick's Day is not just a huge boost for drinkers of Guinness beer, but Irish whiskey as well, said John Quinn, Global Brand Ambassador for Tullamore D.E.W. Irish Whiskey. Tullamore D.E.W. is the second largest Irish whiskey in the world, after Jameson and ahead of Bushmills. Irish whiskey is one of the fastest growing whiskey categories in the U.S. growing 10% in volume and 12% in value in 2014. Tullamore D.E.W. grew 22% in volume and 27% in value last year. Finally, Tullamore D.E.W. went from a 68,000 case brand in 2010 when William Grant & Sons purchased the brand to a 141,000 case brand in 2014.