What does a "shotgun" beer mean?

A "shotgun" beer refers to a technique used primarily with canned beer, where a hole is punctured into the side of the can to allow for rapid consumption. This method facilitates drinking the beer quickly, as it creates a pathway for air to flow into the can while the liquid is being poured into the drinker's mouth. This technique is often associated with party or casual drinking scenarios and is popular for its speed and ease.

The other choices do not accurately describe what constitutes a "shotgun" beer. Serving a beer with a cocktail, mixing it with spirits, or brewing beer twice relates to entirely different processes and concepts within bartending and brewing. This highlights the specific nature of the term “shotgun” in the context of beer consumption.