Double blending means that the frappuccino has been blended twice. The blenders in Starbucks have buttons that are connected to a timer that determines the consistency of the drink after blending. When making a frappuccino, the blender runs for a preset amount of time to achieve proper consistency. Blending the drink again to makes it smoother and easier to drink. The resulting drink is a double-blended frappuccino. Some frappuccinos such as java chip, chocolate cookie crumble and mocha cookie crumble may require double blending to break up the chocolate chips.