Body in brewing terms is often described as the thickness or viscosity of a beer as judged by your mouth. The body of a beer is typically described as thin, medium or full. Different varieties of beer are assumed to have a specific body profile; for instance a light lager or pilsner would be expected to have a thin body profile, whereas a stout would have a full body. The term mouthfeel is oftentimes used synonymously with body.
Determining factors in defining and making up a beer’s body include proteins, carbonation level, unfermentable sugars such as maltodextrin, water profile, and alcohol level.