A Swan Neck is a long-neck spout fitted to a cask beer engine (hand-pump) featuring a tall arch resembling the long, curved neck of the eponymous bird. Such a spout is primarily designed for use with a tightly fitted Angram sparkler, a restrictor device that causes the beer to be sprayed into the glass. However, as with regular spouts, sparkler use is optional.
The depth of the spout between the curve and the base generally matches the height of a standard Nonic or Tulip 568-ml (20-oz) pint glass, allowing the beer to be served with the tip of the swan neck spout near or at the bottom of the glass. Such a practice, almost always performed with a tight sparkler attached, is standard in Northern England, Wales, and Scotland, areas where sparkler use is normal. The use of a sparkler will remove carbonation while forming thick, creamy foam on a pint of cask beer, and this form of cask beer service is appreciated by many beer drinkers in the aforementioned regions. If a sparkler is used without a swan neck spout, some beer is often lost because of overfoaming. A fresh glass must be used each time if the outside of the swan neck makes contact with the beer being poured, as dictated by British Health and Safety rules. Contrary to popular belief, beer poured through a swan neck without a sparkler attached will bear little or no difference in carbonation and texture to that served unimpeded through a regular spout. The enmity sometimes directed at the swan neck spout is often misguided because any differences in texture are actually caused by the sparkler rather than the spout itself.