Guinness is hoping to revitalize U.S. sales of its core stout brand with a new brewery in Maryland that will act in part as a marketing tool for its main Ireland-brewed product. After a 20% surge in January and February exports to the U.S. (ahead of St.Patrick’s Day) there has been an 11% slump in the three months to May 31 which in turn followed a 4% drop in 2017. That’s a similar fate to that seen by other beer imports from outside North America which were probably unchanged in the second quarter after a 6% slide in the first. Shipments from Mexico to the U.S. by Constellation and Hein...