By Kathy McLaughlin The Wall Street Journal February 1. 2012 After years of convincing the nation's coffee drinkers that dark-roasted brews are the classiest thing to fill a mug or takeout cup, Starbucks, Peet's, and a new wave of high-end chains are rolling out the exact opposite: light-roasted coffee. The target customers for the new style of coffee are people like Jackie Russell, a retired school administrator in Los Angeles. Ms. Russell's son Ted Russell is something of a coffee connoisseur, who has shared his passion for Peet's dark-roasted coffee with his mother. Only problem: She hates it. "It's really just a terrible taste to me. It almost tastes like something that has burned," says Ms. Russell. To capture customers like Ms. Russell, Starbucks Corp. in January introduced Blonde Roast, a light-roasted blend now sold in the chain's 10,787 U.S. stores and which will be stocked in grocery stores this week. Peet's Coffee...