Good one.
That's how the nonalcoholic beer was made in the past: http://gizmodo.com/the-science-of-non-alcoholic-beer-509674407
In short, beer boils at lower temp. than water, so all what Cody and Joe had to do is to bring it to the boiling point for a second or two.

By the way, calories in various beer: http://www.fitsugar.com/Calories-Popular-Beers-1504697

Sierra Nevada Bigfoot 330 cal!