The role of Brewmeister Smith was written with Max von Sydow in mind. But Rick Moranis and Dave Thomas thought actually enlisting him would be impossible. They requested von Sydow to the MGM studio, and studio head Freddie Fields telephoned the actor in Stockholm, Sweden and instructed the co-directors to "tell him the story." It turns out that Fields had just recently produced À nous la victoire (1981), which had co-starred von Sydow, so he sent the esteemed actor the script. Instead of hashing it out with Fields, von Sydow ran it by his son, who was a huge Second City TV (1976) fan, and encouraged his father to take the role.
Eh? was spoken 174 times in this movie.
The basic plot as well as many of the names are references to William Shakespeare's Hamlet. The castle in Hamlet was Elsinore. The heir to Elsinore's father was murdered by her uncle, who then comes to her as a ghost. In Hamlet, the uncle's name was Claudius, and in the movie he is named Claude.
Before filming, all of the major breweries wanted the McKenzie brothers to appear in beer advertisements. The filmmakers had the promise of Molson's Brewery, but once the brewery found out that there was a joke in the film about putting a mouse in a beer bottle so that a complaint can be made in order to get free beer, they distanced themselves from the film. The filmmakers were also banned from filming in a Brewers Retail store, and from using the name "Brewers Retail." They ended up building a replica of the store at a cost of more than $45,000, and calling it "The Beer Store." Ironically, Brewers Retail later changed the name of its stores to "The Beer Store," and they continue to operate under that name.
A sequel to the film, entitled Home Brew, was planned for production in 1999, but financing fell through at the last minute. Co-written by Dave Thomas and Paul Flaherty, Flaherty was also going to direct, and Dan Aykroyd was on board to play the part of friend Rick Ripple. Principal photography was to begin on July 19th, 1999 in Toronto, Ontario, Canada. At one point, Todd McFarlane was to step in as executive producer to revive financing for the film, but it never followed through. The plot of this follow-up, according to a Maple Palm release, would feature Bob and Doug, now working as garbage men, being convinced by a fast talking insurance salesman (Aykroyd) to get into the micro-brewing business.