Grub Street recently got an advance copy of tip jar advocate Steve Dublanica's new book "Keep the Change: A Clueless Tipper’s Quest to Become the Guru of the Gratuity," which is chock full of rules for how to tip. Besides splitting tips for sushi chefs and tipping on buffets, Dublanica takes a look barista tipping trends. At Starbucks, one barista says a 50 cent tip is "really generous," while at Portland’s Ristretto, baristas expect to be tipped $1 a drink like a bartender. Unless they sneak Irish Coffee into that carboard cup, we'll stick to leaving our extra change.