Which coupler do most American kegs use?

Most American kegs utilize a D coupler, which is designed specifically for serving beers, particularly those brewed with a higher carbonation level or those that are filtered, such as many American and European ales. The D coupler uses a pressure system that effectively releases gas to help maintain carbonation and provides a steady flow of beer.

The D coupler is distinguished by its unique mechanism that connects to a specific fitting on the keg, allowing for efficient dispensing under pressure. This type of coupler can be used with a variety of beer styles commonly served in the United States, including standard lagers and ales, making it the most prevalent choice in American bars and restaurants.

Other couplers, while serving specific purposes for niche styles or foreign beers, are not as widely employed in the American market. For example, the A coupler is typically used for certain English ales, the B coupler for some European kegs, and the C coupler for different beer types that may not be as commonly found. Thus, the D coupler's versatility and compatibility with a wide range of popular American beers solidify its status as the dominant choice for keg systems in the country.