GUINAN: It's a Tzartak aperitif. It's very, very touchy. The trick is to change the evaporation point of the main ingredient. You want the temperature where the liquid goes to vapour to be a half a degree below the body temperature of the customer. That way, when the liquid touches the tongue, it evaporates, and the flavour is carried entirely by the vapour. A few molecules off, the vapour point crashes, and poof! It's all gone. All of it.