Starbucks debuted a Witch's Brew Frappuccino on Thursday, in another bid to win over Instagrammers with a colorful, bizarre beverage. <br /><br />Dunkin' Donuts announced on Wednesday it is relaunching its espresso line to win over coffee snobs. The coffee giants are battling for both high-brow and low-brow customers as they try to boost beverage sales. <br />
