A Hit to the Bottle

So why exactly does it foam, NPR has the answer.

Rodriguez and his team have figured out that a stiff hit on the bottle's top sets off miniature explosions inside the beer. These tiny blasts create mushroom clouds similar to those generated in the air by an atomic bomb.

"Actually, the laws of physics that control the development of these beer mushroom clouds are the same as [those that drive] the development of the cloud in an atomic bomb," Rodriguez tells The Salt. "Obviously, there's no nuclear stuff in the beer. So the source of the explosion is very different, but the mushroom cloud that you see is very similar."