The air lock helps to release the overpressure from the fermenter, but also prevents, for example, bugs from getting in. In addition, during active fermentation, the activity of the beer can be monitored by the intensity of the bubbling. The latter will only be visible or audible if the fermenter is closed all the way. This type of air lock is capable of discharging large quantities of gas and can even be cleaned in a dishwasher, as it can be completely dismantled.