| From: Mark | 18/03/99
17:06:16 |
| Subject: Guinness & Widgets | post id:
4313 |
| Can someone please explain
exactly how a Widget works. It's obviously reacts to the pressure being released when the can is opened...but how & why?? Regards, Mark. PS: It certainly works...what a drop!! | |
| From: Dr. Ed G (Avatar) | 18/03/99
17:57:01 |
| Subject: re: Guinness & Widgets | post id:
4317 |
| I wish I had a pint of Murphy's
for every time I've answered this question... I'd have, oooh, about five
pints... :-) ... but it hasn't been asked for at least 3-4 months, and
even I'd find it a bit of an ask to look that far back in the archives, so
here goes for pint number six. Guinness, as opposed to say, Toohey's Old, uses nitrogen (as opposed to carbon dioxide) to get it bubbles, because that's the style of a Irish Stout! It gives the beer a smoother taste (because the solution of CO2 and water creates an acid [carbonic acid to be specific]) and a rich creamy head (because nitrogen bubbles are smaller than CO2 bubbles - this is because CO2 bubbles continuously grow as the CO2 comes out of solution in the beer). 200 years ago the nitrogen was added to the beer using a special aerating tap head (not completely dissimilar to the wire mesh tap head you put on your water tap at home - except the pressure inside the head as you "pulled" the beer was much greater). These days, however, they add it either to the keg, or via a widget to the can. The object which gives your draught Guinness in a can its head, now commonly known as a "widget", and was invented by Guinness in the 1980's. It is simply a small piece of plastic with a small hole leading to a small volume of air, which of course, is mostly nitrogen. This widget is placed into the can before the Guinness, then the Guinness poured in, and the can is sealed. Apparently then (according to the Guinness website), the Guinness becomes naturally pressurised, which forces a small amount of Guinness (1%) into the widget. This small amount of Guinness, as a result, displaces and therefore pressurises the air within the small volume of the widget. When the can is opened, the entire contents come back down to atmospheric pressure. More importantly, the pressurised air in the widget gets forced out through the small hole in the widget with a great FIZ, aerating the beer in a similar manner that it was 200 years ago, and voila, a perfect creamy head. While such nitrogenation is used principally for Irish Stouts (the very best of which, in my humble opinion, is Murphy's, not Guinness), other beers also use nitrgenation (using the same widget developed by Guinness under licence) for a smooth creamy taste, such as Abbots Pale Ale, and Boddingtons (the Cream of Manchester), to name just two. Soupie twist, Ed G.  | |
| From: MichaelT | 28/07/99
22:53:54 |
| Subject: re: Guinness | post id:
26764 |
Interesting... I met a guy in the mid-eighties soon after those widgets came out who claimed to actually work in the factory that makes the guinness, and took great delight in pulling the thing out of the empty cans and explaining its inner workings. The way he explained it was that the widget was pressurised, and a tiny laser hole put in it. This hole was so small that when the can was pressurised, the pressure difference between the inside and outside of the widget was not great enough for gas to escape the widget. When the can was opened, the pressure difference allowed the gas to escape into the guinness. Does this sound plausible? Regards, MichaelT | |
| From: Dr. Ed G (Avatar) | 29/07/99
1:02:53 |
| Subject: re: Guinness | post id:
26769 |
| It's more a case of forcing
Guinness into the widget when the can is pressurised than stopping the gas
(mostly N2) getting out. Once the liquid gets into the widget
it falls to the bottom of the widget's cavity, so that when the can is
depressurised (i.e. when it's opened) the pressure inside the widget
forces the air out, aerating the Guinness in the can. The reason the gas in the widget doesn't leave which inside the sealed can is related to the small size of the hole, and the surface tension of the Guinness at the hole's entrance. If the hole was bigger the gas would indeed escape the widget before the can was opened (and if it was too small no Guinness would be able to enter the widget to pressurise the gas in the first place). Soupie twist, Ed G. | |
| From: Chris W (Plebeian) | 29/07/99
9:01:53 |
| Subject: re: Guinness | post id:
26794 |
I can't see how this creates a plethora of bubbles. Have I missed something? | |
| From: Dr Paul (Avatar) | 29/07/99
9:43:43 |
| Subject: re: Guinness | post id:
26799 |
| Hi Chris, Hi Craig, Hi Dr
Ed, I am also in a need for logic. If you place a small sphere at atmospheric pressure into the can, put the Murphy's in, seal the can, heat to pressurize, small amount of stout gets into the widget. How can the head become 1/3 the volume of the beer. A couple of logic items need to be clarified, does the Murphy's (it never bitter about being brewed) and/or guiness get pumped into the can under N2? This may increase the N2 content in the solution in the can. If super cooled, the N2 may super saturate compared to drinking temp of 5-8C. Is the widget pre-pressurized? The can is then loaded with widget and filled with stout (mmmmmm, irish stout) under N2 pressurized atmosphere? If, when the can is opened, the widget is to provide a significant Fizzzzzzz, the system will need to be more pressurized than a few 10's to 100's of microlitres of gas. (Stout seepage into the widget). I would expect to get a real fizz out of a widget, the can to be pre-pressurized and the solution to be supersaturated with gas. Under these conditions, N2 would be my gas of choice, inert, large temperature variability in gas solubility. CO2 would form carbonic acid, altering the chemical nature of the stout (the 11th commandment is DO NOT STUFF AROUND WITH THE NATURE OF IRISH STOUT). Are we getting closer to the solution to the widget yet Dr Ed?? Paul , an enjoyer of Beers from the Islands of Western Europe. | |
| From: Cam (Avatar) | 29/07/99
10:16:36 |
| Subject: re: Guinness | post id:
26807 |
Your description of the process sounds reasonable. But have a look at Ed's explanation. When the can is pressurised (by natural fermentation?) liquid enters the widget through the holes in the top, pressurising the gas. When the can is opened, it's usually held upright. So the liquid is at the bottom of the widget and does bugger-all. But the gas escapes through the holes at the top of the widget. Note that the volume of froth does not have to be equal to the volume of gas in the widget. All that the escaping gas needs to do is provide nucleation sites for the natural fizziness of the Guinness. The Guinness would develop a head anyway, the widget just helps it along a bit. | |
| From: Cam (Avatar) | 29/07/99
10:22:09 |
| Subject: re: Guinness | post id:
26809 |
| Bugger! stuffed up the colour in
the last post. That first line was a quote from Chris
W. Boddingtons ale also has a widget, but it's not fixed to the bottom of the can like the ones in Guinness. It's free floating. I guess it has several holes around the edg of the widget to ensure that gas will come out rather than liquid. | |
| From: Chris W (Plebeian) | 29/07/99
10:41:18 |
| Subject: re: Guinness | post id:
26811 |
| Fixed to the bottom... that
helps, now I see how gas escapes from the widget. Spot the non-drinker! | |
| From: greg | 2/09/99
22:55:05 |
| Subject: re: Guinness | post id:
34804 |
| The can of Guiness I enjoyed had
a floating widget also, Just like this other stout Boddiington's, perhaps
it's Murpheys' that has a widget stuck to the bottom. THE WIDGET HAS CHANGED THE FACE OF STOUT IN A CAN FOREVER. When they brought my can to the table i was rather upset. I imagined a nice frother pint from the tap and this waiter wacks a can on my table. I bought a can about two years ago and vowed never to again. As soon as i poured my beer though my did backflips, this was looking almost as good as a guiness out of a tap. The taste passed the final test with leaps and bounds and i had a marvellous night for it. so there you go Cam | |
| From: Mac | 2/09/99
23:08:16 |
| Subject: re: Guinness | post id:
34807 |
| That is because the Guiness,
Cafferys etc is imported from Ireland not the bilge water brewed here and
sold as Guiness pre-widget. If you haven't guessed..."I like to
watch." | |