SEATTLE, 2015-8-25— /EPR Retail News/ — Pumpkin Spice Latte, Starbucks most popular seasonal beverage of all time, marks the return of autumn for many customers. "When you taste PSL, it tastes just like fall,” said Peter Dukes, director of Espresso and Brewed Coffee for Starbucks. As leaves change colors and fall nears, the product manager who led the development of…