Session drinking is a chiefly British term that refers to drinking a large quantity of beer during a "session" (i.e. a specific period of time) without becoming too heavily intoxicated.[3] A session is generally a social occasion.
A “session beer”, such as a session bitter, is a beer that has a moderate or relatively low alcohol content.
In the United States, a recent session beer definition has been proposed by beer writer Lew Bryson. His Session Beer Project blog includes a definition of 4.5% ABV or less for session beer. Followers of this definition include Notch Brewing, a session only beer brand. The Brewer Association has adopted a new category within their Great American Beer Fest competition which states a "session beer" must not exceed 4.1% ABW (5.1% ABV). [4]