In most cases, a coupler is used to connect the nipple to the ball valve. The plumbing system of a home brewing station requires a delicate balance. The couplers and other hardware create resistance to the pressure that affects the flow of the liquid.
Aside from being an essential part of the plumbing system of the brewing station, couplers also create various connections. It can be used as an adapter to customize the brew pot. Devices or equipment that use couplers may include thermometers, sight gauges and many others. When using couplers to connect different brewing equipment, it is crucial to determine the type of threading used. For instance, if the coupler features a female pipe thread, the attached hardware will have a male pipe thread for compatibility. (more info below)