Session beer is a term used to describe a beer that is lower in alcohol content, generally under 4 or 5% ABV, and high in refreshment. It is not a specific style of beer, but rather an adjective used to describe beers that are not too filling and not too bitter, hoppy, or malty. The term "session" comes from the idea that you can enjoy a few of them in a drinking session and still have your wits about you. The purpose of a session beer is to allow a beer drinker to have multiple beers within a reasonable time period or session without overwhelming the senses or reaching inappropriate levels of intoxication.

Different brewers have different definitions of what session beer means to them, and the term is majorly subjective. Any beer style can be made lower in strength than the classic style guidelines to become a session beer. Some examples of sessionable beer styles include Pilsner, Witbier, Kolsch, Blonde, Hefeweizen, Pale Ale, Gose, and Berliner Weiss. The origins of the session terminology are not entirely clear, but it seems that most versions point to the term "session" defined in British legislation back during World War I, which allowed English factory workers to drink on the job during their lunchtime and evening sessions.

In summary, session beer is a beer that is lower in alcohol content, high in refreshment, and allows a beer drinker to have multiple beers within a reasonable time period without overwhelming the senses or reaching inappropriate levels of intoxication. It is not a specific style of beer, but rather an adjective used to describe beers that are not too filling and not too bitter, hoppy, or malty.