IMO, it's very important to build a cake all the way to the bottom. It's tricky and takes time, you don't want to scorch the airway. In any event, the only way to build a cake at the bottom is to smoke to the bottom. I learned this lesson from a friend that always smoked his pipes to the bottom and wondered why he put himself through the pain of smoking to the bottom. Then I checked out one of his pipes, cake all the way to the bottom! So I started to do this and they smoke sweet as a nut all the way down