So I’ve had a few of these Guiness draft things this evening. I was intrigued by the technology behind this so I ripped open a can. I was surprized to find only a plastic ball inside. What’s up? How does it work?
The Guinness (Yes, TWO n’s) website has a pretty good explaination at www.guinness.ie
I was puzzled by this myself, but a patent search turned up this It’s a long description and has some pages of images relating to the widget, their term for that ball. Also check out the Guinnesssite. It has a simpler description.
Hey, cool simul-post!
Man… that’s funny you ask this. I just got back from my trip to Hawaii 
. While I was there, I had a peculiar experience. Stouts are my favorite beers, and since they are not very popular, Guinness is about the only one you can find in most restaurants (that’s if you are lucky). This being the case, I ordered one when the waiter came around. He told me that all they had was Guinness in a can, and asked if that was still what I wanted. I said “sure”. When it was brought to me, I opened it and poured it into a glass. After I was done pouring, I righted the can to set it down, and felt a slug of ice hit the bottom of the can. Since the beer was cold (damn it… I like my Guinness warm, but forgot to ask for such), I didn’t think anything of the ice being in there, and left well enough alone.
When I ordered my second beer, I had the presence of mind to request an unrefrigerated beer. When I received it, I poured it into the glass the same as the first one, and just like the first one, it had ice in it… what? Ice? In my warm beer?
I had to know what was up. I ripped the can open, and extracted a Ping-Pong ball… what? A Ping-Pong ball? In my beer?
I was baffled. Everyone at my table was offering suggestions as to what it was for. None of them satisfied me. They were offering things like, “Maybe it instantly carbonates the drink right when you open it.” Nah, that much carbonation decompressing would also have the effect of chilling the beer, which did not happen. “Maybe it acts like the little metal ball in a spray paint can… you know… to keep it mixed up.” Nah, what??? Are you supposed to shake your beer before you open it? You’re only supposed to do that just before you hand a beer to your dad. The suggestions didn’t get any better than that.
When I got home, I looked up the Guinness Web site, and found… oops… I just did a “refresh” of the thread, and saw that others have, in effect, posted what I found out.