Fred:

Mechansim is quite simple, before the beer is placed in the can (or bottle
or keg), it is carbonated and nitrogenated to precise levels in a holding
tank. Here in the USA this tank is known as a bright beer tank. As the
empty cans/bottles move down the conveyor toward the filler, a special
machine places a widget in each can/bottle. The widget is esentially a
hollow plastic sphere or other shape, and other than holding the widget in
place in the can I don't believe that the shape has any major role. However
the secret is that just before the widget is placed into the can a laser
cuts a hole of a precise diameter in the widget. The can is then filled and
sealed in the conventional manner.

After sealing, the higher pressure in the can relative to the inside of the
widget results in the widget filling with the beer until the pressure inside
the widget reaches an equilibrium with the rest of the can. Things then
remain stable until the can is opened. When the can is opened, the pressure
in the bulk of the liquid falls, faster than that of the liquid inside the
widget. As a result of this differential pressure, the liquid in the widget
squirts out through the orrifice, this sets up shear forces that strip the
nitrogen from solution in exactly the same way as the restrictor plate is a
"stout faucet" does. The nitrogen forms the dense creamy bubbles that give
the characteristic creamy head.

As for making all beers taste the same, I believe that this is a side effect
of the niotrogenation. My experience is that the nitrogen tends to strip
hop bitterness from the liguid into the head. I know this sounds gross, but
use your finger to scoop out some of the head and taste it, typically it
will be bitterer than the liquid, hence the beer will have that same
relatively bland smooth taste.

Iechud Da - Cwrw42


"FredG" > wrote in message
om...
> Greetings all.
>
> How do the plastic inserts (widgets?) in draughtflow cans work? Also
> is it an additional function of these things to make all beers taste
> the same or is it just me?
>
> Thanks.