Bryan wrote:
> Doug Freyburger > wrote:
>
>> I wondered if canning made the beer crappy or if only crappy beers were
>> put into cans. *Which was the cause and which was the effect? *The
>> answer for me came when Guinness invented the can with the nitrogen jet
>> pellet. *Canned Guinness is now clearly better than bottled Guinness.
>> The answer is in the past it tended to be the crappy beers that went
>> into the cans. *The rule that only canoe beers are canned expired with
>> the Guinness can.
>
> They don't put the good Guinness into cans (Extra Stout) do they?

Absolutely. The cans are patented and I'd had other stouts that used
the exact same can. The can is pressurized with nitrogen. Inside the
can is a pellet that's a little bigger than the hole at the top. The
pellet is a sphere with one point put off.

What happens is over time the amount of nitrogen in solution stablizes
at all points inside the can including inside the pellet. The pressure
is high and uniform throughout the can. When the top is popped most of
the inside of the can depressurizes immediately. The pressure is then
higher inside the pellet because the hole is too small for the pressure
to release in a faction of a second. Nitrogen starts to come out of
solution inside the pellet and there's a jet of turbulant nitrogen
bubbles. The Guinness in the can ends up with the same fine nitrogen
foam that you see with Guinness from a keg. It's a brilliant
application of fluid dynamics.