and Ric informs us:
> 
> The other night on "invention" or some such program was a 5 minute blurb 
> about the process used to make Guinness Stout from a can look and taste like 
> Guinness Stout from a Pub. Anywho, the short of it is there is a small 
> nitrogen bladder in the can which releases its stuff when the can is opened, 
> and when the contents of the can are poured into a tall 16oz glass, VOILA, 
> you have the classic Guinness head.

that device is actually a fairly ingenious pressure reservior with a 
"needle and seat" that bleeds the proper amount of nitrogen into the 
stout as needed.  nitrogen and just air blending with brews gives a 
creamier head without increasing the twang from adding more 
carbonation.

now, here's the kicker.  there is a warning label on the can that 
warns against opening the can and investigating the device.  so 
naturally, i had to see one.  it is made out of a HDPE and is a 
model of simplicity.  it also contains enough pressure to 
explode (well POP really loud) and send a piece of the thang flying 
when i started prying on it.  

"You Could Poke An Eye Out"  so *be careful*.  and it IS worth 
investigating!  well, if you like stout...  and if you like geek.

-dan (who likes both)