At this point, you can finally "chillax" and let the whiskey still do its job. A built-in thermometer will tell you when your mixture is around 172 degrees. Why does this matter? What a hell of a question. At 172 degrees, alcohol evaporates—unlike water, which evaporates at 212 degrees. The evaporated alcohol goes up the tube and into the adjoining vessel, giving you pure, untouched booze.
At this point, you've got moonshine and—if you like moonshine—you can just drink this high ABV liquor by itself, but if you want delicious whiskey, you must age your creation.