Small beer is a
beer that contains very little
alcohol, perhaps less than one percent. Sometimes unfiltered and porridge-like, it was a favored drink in
Medieval Europe and colonial
North America. It was sometimes had with breakfast, as attested in
Benjamin Franklin's autobiography. Before public sanitation
?, water-transmitted
diseases, such as cholera
?, were a significant cause of death. Because alcohol is toxic to most water-borne pathogens, drinking small beer instead of water was one way to escape infection.
Metaphorically, small beer means a trifle, a think of little importance.