Abstract: A fermentation device and a method for making a substance using the device are provided. The fermentation bung may have an outer plug that includes a central inner annular hole and a one or more holes surrounding the central hole, the outer plug fitting within a bung hole in a barrel in which a substance is going to be fermented. The device may further include an inner plug with a centrally extending stem that frictionally fits into the central inner annual hole of the outer plug to secure the inner plug into the outer plug and also have a top portion which covers the one or more holes surrounding the central hole. During the fermentation of the substance, the gases produced during fermentation may be vented through the device since the top portion of the inner plug may flex slightly to permit the escape of the gas. However, the device prevents any ambient air from entering the barrel since the top portion of the inner plug is covering the one or more holes.