"Lactose is a really interesting sugar," says Truman Severson, his hands punctuating his words. His hair side-slicked as though he were Clark Gable, complementing an Eton College professor outfit of a tie, brown tweed vest and browline glasses. On a Saturday afternoon, he holds court at Theorem, a six-seat tasting bar inside Portola Coffee Lab in Costa Mesa. He has just poured from a steel kettle a stream of water heated to 203 degrees, in a steady, circular pattern over dry coffee grounds resting in a shiny, chrome dripper that resembles an... More >>>