In lieu of a 21 gun salute (i.e. lack of firearms and ammo) the 21 beer salute is sometimes performed by the bros of a fallen comrade. A group of seven bros shotgun three beers each. 7 times 3 equals 21, thus the name 21 beer salute.
When the crew lost Chad the bros gathered to pay their respects to their fallen bro by performing the 21 beer salute. they then proceeded to get kicked out of the wedding reception by security for partying too hard.
by BroCodeBible September 22, 2016