A Siphon, or vacuum coffee maker, is a “full immersion” brew system. That means instead of boiling the coffee it uses a constant heat source (the burner) to create an internal vacuum that moves the water from one chamber to the next.
One of the main advantages of a vacuum brewer is that the water never reaches boiling, which causes the coffee to lose some of its most subtle flavors. With a Siphon, once the burner is set the temperature remains constant for the entire brew-cycle. This full “immersion” method is ideal, as the coffee grounds are all immersed in the water for the same amount of time, with the same amount of heat, continuously.