I went to my local pub and have that thing that makes Guinness beer bottle as most draft, what is?
It has a sign on Guinness and a round metal plate. The bartender put a little water into the dish and then placed the glass on it. He pushes a button and instantly the beer had a head on it. She said it was a kind of electrical current. What is your name and how it works?
It's called "Guinness Surger" uses sound vibrations to release nitrogen gas into the beer to cause the foamy head. And it only works with the beers that have the nitrogen widget. http://gizmodo.com/gadgets/gadgets/guinness-surger-160488.php