[math-fun] minimalist beer froth

I’d be interested if anyone can reproduce the following effect I observed earlier this evening when dispensing a bottle of Sam Adams Boston Lager. The key, I believe, is to empty the bottle into the glass as quickly as possible by upending the bottle above the glass. Use a large glass and don’t be distracted by the large amount of foam that is generated in the glass. Focus instead on the geometry of the minimal (beer film) surfaces left behind in the bottle. To my astonishment, there were eight flat films roughly evenly spaced along the length of the bottle! -Veit