What is the primary function of couplers in a draft system?

The primary function of couplers in a draft system is to allow gas into the headspace of a keg. When a keg is tapped, the coupler creates a connection between the keg and the draft system, enabling the introduction of gas, typically CO2 or nitrogen, into the keg’s headspace. This gas pressure is essential as it pushes the liquid beer up through the distribution lines and out of the tap, ensuring a consistent flow of beer when the faucet is opened. The function of allowing gas into the headspace is critical because it maintains the appropriate pressure required to serve the beer without introducing excessive agitation.

While cooling the beer is vital for overall serving conditions, couplers do not perform this function; instead, they operate in tandem with refrigeration systems. Filtering impurities can be an important part of the beer's conditioning and serving processes, but couplers themselves are not designed for filtration. Regulating keg pressure is indeed important in a draft beer system; however, this function is more closely associated with pressure regulators rather than couplers. Thus, the correct focus on the coupler's role emphasizes its critical purpose in managing the flow of beer by facilitating the necessary gas supply.