What is the primary benefit of using a single cask with a double-ended tap for dispensing?

Using a single cask with a double-ended tap facilitates better flavor preservation. When beer is stored in a single cask, it minimizes the exposure to oxygen compared to a multi-cask system, significantly reducing the risk of oxidative spoilage. The double-ended tap system allows for two separate serving lines to draw beer from the same cask, which helps ensure that the beer remains intact and protected from the external environment when being served. This method also prevents unnecessary agitation of the beer, which can lead to off-flavors, thereby maintaining the integrity of the beer's flavor profile over time.

In contrast, while smaller casks might keep better and larger casks provide more beer, these factors do not specifically address the preservation of flavor. The maintenance of consistent serving pressure is also a consideration but is not as directly related to flavor preservation as the effects of minimizing oxygen exposure and agitation. Thus, the choice focused on flavor preservation is the most relevant benefit of using a single cask with a double-ended tap for dispensing.