From: Ronald Wong (ronwong@inreach.com)
Date: Wed Feb 23 2000 - 23:43:51 PST
Date: Wed, 23 Feb 2000 23:43:51 -0800 (PST) Message-Id: <l03102800b4d9a7ead3da@[209.209.19.93]> From: Ronald Wong <ronwong@inreach.com> Subject: Guiness Draught
Heidi asked:
>OK beer drinkers, anybody out that can tell me about the little floating
>ball in the Guiness can? Supposed to break up little frothy bubbles of
>gas??
When Guinness is drawn from a tap, it starts out as a liquid under high
pressure which then passes through a series of fine holes in the tap before
tumbling into the customer's glass.The constriction coupled with the sudden
drop in pressure produces the very fine bubbles that lead to the smooth,
stable head that you can write your initials on.
Quite a number of gadgets were developed, starting in the 1980's, to
replicate this effect in the canned and bottled versions of stout beer.
They ranged from a separate compartment at the bottom of the can that
contained a gas under high pressure, to a gas absorbed onto the surface of
a folded sheet of a light plastic material placed inside the liquid, to a
hollow gas-filled plastic container that floated around inside the bottle
(someone posted a question asking about this) or can. The gas was usually
nitrogen.
Typically, a valve or two was involved. For instance, one version had a
valve on the top and bottom of a plastic cylinder that floated on the
surface of the beer. After the liquid was poured, the gadget followed and
then nitrogen gas was introduced and put under pressure. Under pressure,
the gas entered the cylinder through the valve at the top and remained
there under high pressure. When the bottle/can was opened, the pressure
surrounding the cylinder fell to atmospheric pressure and the gas inside
would escape through the one-way valve at the bottom. The rapid injection
of the gas into the liquid produced the head.
I'm pretty sure the ball you described is a variation on this theme. From
Jeff Furman's discription, it's apparently been simplified to a large
degree (the can with the separate compartment mentioned above is Guinness'
original patent for their product).
The next time you have a chance to engage in a Guinness, you might like to
apply your proven powers of observation to the brew as it sits in its glass
container. Pour the Guinness into the glass and watch the bubbles as it
settles down. Do the bubbles clinging to the inside of the glass migrate up
or down the sides of the glass? - Mind you, the glass should be the classic
shape with its tapered sides to get the best results.
Compare your results with others and explain why it should be so.
By the way - Until the invention of the gas/beer injection device that you
discovered in your can of Guinness, the word "widgets" was just another
generic term for what others would call a gadget. Apparently, the beer
industry has proclaimed that these injection devices are to be known as
widgets from now on. Whether this will appear in the OED as such remains to
be seen.
ron
This archive was generated by hypermail 2b29 : Thu Oct 19 2000 - 11:10:37 PDT