Liquor giant Diageo PLC said Monday it is opening a visitors' center at Stitzel-Weller, part of a $10 million investment that includes a new bottling line and a small batch craft still that will bring whiskey production back to the distillery southwest of downtown Louisville. The Bulleit Frontier Whiskey Experience at Stitzel-Weller becomes the ninth stop on the Kentucky Bourbon Trail, said Eric Gregory, president of the Kentucky Distillers' Association.