I subscribe to the Sixty Symbols YouTube channel which is produced by the University of Nottingham, and today, I noticed they had a new video on a subject near and dear to many a physicists heart: Guinness.
If you think that beer is beneath the interest of physics, you should surf on over to Amazon.com and check out Craig Bohren's Clouds in a Glass of Beer. It is an excellent accessible book on atmospheric physics that examines (among other topics) the way that bubbles form in beer. It's a creative, informative book that presumes no great knowledge of physics, but can help remove some of the many misconceptions we have surrounding atmospheric physics and weather.
If that doesn't satisfy your need for equations, you can try this rather beefier exposition, entitled Waves in Guinness.