Pub Draft Guinness
Mark Shaw
What is the thing in Pub Draft Guinness? How does it work?
Where can I get it? The thing is a can that has a widget in it
that is used to produce a creamy head as you pour the beer.
Probably the closest thing to "draft beer in a can!"
Okay, fine -- but what is the widget? How does it work? More
importantly (in terms of the argument another person and I are
having on another newsgroup), does it release CO2, or Nitrogen,
or what?
Thanks in advance.
---
Mark Shaw
My opinions only
PGP public key available at ftp.netcom.com:/pub/ms/mshaw
Joel_Plutchak
> The widget is attached to the bottom of the can (on the inside).
>There's a technical answer to this question floating around somewhere
>in netspace...
Found it... it's available in Alan Marshall's celebrated "Guinness FAQt
and Folklore" document:
ftp://ftp.stanford.edu/pub/clubs/homebrew/beer/rfdb/beer-guinness.faq
http://www.ivo.se/guinness/
It's located about halfway through the document, in section III, Guinness
FAQs. There's also some technical info from the patent in Appendix II.
Joel_Plutchak
>From the FAQ:
>
> What is the thing in Pub Draft Guinness? How does it work?
> Where can I get it? The thing is a can that has a widget in it
> that is used to produce a creamy head as you pour the beer.
> Probably the closest thing to "draft beer in a can!"
>
>Okay, fine -- but what is the widget? How does it work? More
>importantly (in terms of the argument another person and I are
>having on another newsgroup), does it release CO2, or Nitrogen,
>or what?
The widget is attached to the bottom of the can (on the inside).
There's a technical answer to this question floating around somewhere
in netspace, but the simple answer goes something like this. The
widget is a plastic capsule that has a pin-prick hole in it. At
bottling (canning?) time, nitrogen is pumped into the can, which
forces some beer into the widget. When you open the can, the force
differential causes the beer in the widget to squeak out of the
pinprick hole, causing the tiny bubbles to give it the ultra dense
creamy head.
AFAIK, the more common answer, which states that the widget is
filled with nitrogen, is not strictly correct based on my reading
of the technical description when "Pub Draught" Guinness first showed
up in the States.
Tom Donaghue
>
> From the FAQ:
>
> What is the thing in Pub Draft Guinness? How does it work?
> Where can I get it? The thing is a can that has a widget in it
> that is used to produce a creamy head as you pour the beer.
> Probably the closest thing to "draft beer in a can!"
>
> Okay, fine -- but what is the widget? How does it work? More
> importantly (in terms of the argument another person and I are
> having on another newsgroup), does it release CO2, or Nitrogen,
> or what?
>
>
> ---
> Mark Shaw
> My opinions only
> PGP public key available at ftp.netcom.com:/pub/ms/mshaw
The following is from the guinness FAQt and folklore Web Site,
located at: http://www.ivo.se/guinness/ Visit this wonderful
site to settle any and all Guinness-related arguments.
======================================
"Patent Information on the Smoothifier
"Robert James bobj...@delphi.com posted: I was doing some patent
search work at the Washington library in Chicago the other day
and I ran across no. 4,832,968, the U.S. patent for the Guinness
in a can stout.
"The basics:
Inventors: Alan J. Forage & William J. Byrne
Assignee: Arthur Guinness Son & Co., Ltd.
"Process:
The gas pod in the can is blow molded with nitrogen (N).
A laser zaps a hole in the pod. (they experimented with holes
between 0.2mm and 2.5mm finding that 0.61 mm as ideal).
Pod is inserted in the bottom of can.
Can is filled with CO2/N supersaturated stout. N is present
at 1.5% v/v min up to 3.5% v/v. (FYI, vol/vol is the number
of volumes of gas which are dissolved in a unit volume of
beverage at 760mm of Hg & 15.6 oC) CO2 is present at between
0.8 and 1.5% v/v.
"During filling, foam rises to top of can. This clears the air.
A charge of liquid N is added to the stout.
Can is sealed.
As liquid N boils off in can during pasteurisation (60 oC for
15-20 min), top of can pressurizes and forces the stout into
the pod, thus compressing the ambient pressure N in the pod.
Equilibrium is reached at about 25 psi.
"As I interpret the patent, this is what happens when the can
is opened:
The can quickly depressurizes to ambient pressure. The pod thus
expels the stout contained in it (about 10-15 ml) at high velocity
through the orifice. This causes high local strain of the stout
at the plane of the orifice. This strain exceeds the cohesive
forces holding the gases in solution. As a result, the N/CO2 is
liberated from the stout at the plane of the orifice. The millions
of tiny N/CO2 bubbles then become the foam head. So contrary to
my initial belief, while some of the N gas in the pod escapes
directly into the stout, it is actually the "ripping apart" of
the stout as it exits the pod which produces the bubbles, hence
the creamy head."
======================================
Tom Donaghue
Erik R. Batzloff
<stuart...@ccm.jer.intel.com> wrote:
>As for what the Widget is. I remeber hearing about it on one of those
>programmes on T.V. where they explain to you all the breakthroughs in Hi
>Tech. As I recall the widget is a small capsual of Nitrogen at the top
>of the can. When the can is opened the Nitrogen capsual is opened at it's
>bottom end. Due to the presence of the piss (don't forget we are talking
>about Guiness) it cannot escape downwards. However as the can is poured
>it bubbles through the urine giving it froth.
>It might be an intresting project to investigate whether or not the
>testicles in small furry animals have the same effect. As everyone knows,
>badger pee is perticularialy frothy.
You're out there a mite, ain't ya? Like you already. But, there's nothing
like Old Hoss brew being wizzed on a flat rock.
Oddsocks
Joel_Plutchak
>In article <4i9ggr$c...@spock.asic.sc.ti.com>, ms...@asic.sc.ti.com (Mark Shaw) says:
>>
>>Okay, fine -- but what is the widget? How does it work?
>>
>pulling the tab will force its way from the top of the can to the
>bottom of the can aerating the beer, open a can up and look at it.
Wow, it's amazing the kinds of answers you find, especially after
at least two people posted the correct answer. I kinda like the one
above, though. :-)
--
Joel Plutchak (plut...@uiuc.edu), Research Programmer
Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign
ecol...@midway.uchicago.edu
>
> What is the thing in Pub Draft Guinness? How does it work?
> Where can I get it? The thing is a can that has a widget in it
> that is used to produce a creamy head as you pour the beer.
> Probably the closest thing to "draft beer in a can!"
>
>Okay, fine -- but what is the widget? How does it work? More
>importantly (in terms of the argument another person and I are
>having on another newsgroup), does it release CO2, or Nitrogen,
>or what?
>
>Thanks in advance.
>
>
>
pulling the tab will force its way from the top of the can to the
bottom of the can aerating the beer, open a can up and look at it.
>Mark Shaw
>My opinions only
>PGP public key available at ftp.netcom.com:/pub/ms/mshaw
>
>
Plamen D. Penev
Northwestern University, Evanston, IL. USA
pe...@nwu.edu
John DeCarlo
J> * Newsgroups: alt.beer,rec.food.drink.beer
J> ecol...@midway.uchicago.edu writes:
>>>---That what you call the widget is a nitrogen loaded capsule that
>>>upon pulling the tab will force its way from the top of the can to
>>the bottom of the can aerating the beer, open a can up and
>>look at it.
J> Wow, it's amazing the kinds of answers you find, especially
J> after at least two people posted the correct answer. I kinda
J> like the one above, though. :-)
It's my favorite of all them, too, Joel. Simply amazing.
Those who don't understand the answer above, simply think about a balloon that
you untie suddenly. Remember how they fly around the room at random until it
deflates?
John
Tom Donaghue
Hmmm, methinks you are far too keen an expert on badger pee. You scare me.
Tom Donaghue
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