Guinness Widget

Now for something totally different.

First a bit of historical context.  We ate at a great beer and pizza place in Kearney, Nebraska, last month, Old Chicago Pizza and Taproom.  (See the end of this post.)  In honor of St. Patrick's Day, I had a Guinness which was on tap.  I am not sure if I had ever had a Guinness.  If I had, it had been long long ago.  It was great in so many ways, including the very smooth, creamy foam on the top, which is unlike most other beers.

After returning home I ordered a Guinness while eating out at our local Red Robin.  I knew they would not have Guinness on tap, but they did list it on the menu so I ordered one to see how it would compare to my earlier experience.  It was in a can, but the foam was still that smooth tiny bubble foam like I had had in Kearney.  However, as I got to the end of the can I could hear something rattling around inside.  It was then that I vaguely remembered reading about some special device that Guinness adds to their beer to get the desired smooth foam similar to their beer on tap.

How do they do it?  Almost immediately after that, I stumbled across this explanation on Modernist Cuisine and how it all works.  The important issue is that the creamy foam comes from pressurized nitrogen rather than carbon dioxide as in most beers.  Nitrogen is much less soluble in water than carbon dioxide...more than 100x less soluble at cold beer temperature according to this site.  It hence makes much smaller bubbles. 

Bubbling nitrogen through the beer is relatively easy to achieve if on tap using a tank of nitrogen, but not so easy with a can or bottle.  To get the bubbling nitrogen, Guinness adds a small amount of liquid nitrogen just before sealing the can.  Also in the can is their patented "Widget", a hollow plastic sphere with a small hole.  The increased pressure inside the sealed can after the liquid nitrogen vaporizes forces nitrogen and beer into the center of the widget.  When the can is opened, the gaseous nitrogen comes out of the widget and bubbles up through the beer, forming the foam.

We discover a new (to us) beer store in Flower Mound. This would have been the end of the story, but we happened to see a feature article in the Dallas Morning News about a new (to us) filling station in Flower Mound which stocks over 800 different brands of beer.  I am sure we could have gotten Guinness at other places, but we decided to pick up a six-pack at this place so we could check it out.  It was interesting, with LOTS of different beers.  An additional discovery we made on this trip...Guinness comes in "four-packs" rather than "six-packs".

Taste-wise I am not sure it was quite up to what I had remembered from before, but it did indeed have the creamy foam on top.

Next up was the reason for getting our own cans, ripping one open to find the Widget. Sure enough, the plastic sphere was inside.

 

Opened can with widget

Close up of Widget--a little more than 1 inch in diameter

Pretty cool...especially given the thousands of gallons of liquid nitrogen I have gone through over the years.  And to think that all of these years I have been lecturing to my students repeatedly about not putting liquid nitrogen into a sealed container.  I was always concerned it would explode.  Now off to figure out what volume of liquid nitrogen will produce the amount of gas to fill the Widget but not explode the can.