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Why Bubbles in Guinness Fall
ts4z writes "Reuters reports: 'Australian scientists say they have answered a question that has plagued and entertained drinkers for generations -- why do the bubbles in a glass of Guinness appear to be falling to the bottom?'
I found the full story on Yahoo.
Explains my endless facination with the stuff.
" Hah! Beer and science working together. It's beautiful.
Personally, I think this is the ideal candidate for a screen saver - since none of the Guiness or other beers have Linux versions of their screensavers. I could sit and watch the bubbles fall for hours..
Perhaps their could be options to alter the consistency of the beer, from Guiness to Beamish to Ales... and so on.. with different bubble patterns.
Truly this would be a great feat.
"Patience is a virtue, afforded those with nothing better to do" - I can't remember
"Patience is a virtue, afforded those with nothing better to do." - I don't remember
It's amazing really. In my own very unscientific studies, both bubbles and all the rest of Guinness seem to fall directly to the bottom of my stomach and just as mysteriously, suddenly rise straight to my brain !
I must perform more thorough research into this however before submitting my paper to the journals...
If you don't understand anything I post, please accept that I ate paste as a small boy...
Actually, it's not the same thing at all.
The 'lava' in your lava lamp rises because it is heated by the lamp, and falls because it has cooled.
The bubbles in guiness fall because Guiness is actually of alien origin, from a planet where the laws of physics are not exactly the same. The bubbles fall because they contain a denser-than-beer gas, give the scientific designation DTB01. The beer simply acts as a stabilizing agent.
DTB01 has been shown to have other uses, especially as a method of powering interstellar and time-shifting spacecraft.
Of course, these craft tend to use lava lamps as well, mainly to appease the crew, as they have nothing better to do, especially after drinking the leftover stabilizing agent.
On another note, anyone remember how SGi has their patented method of doing random number generation, using a lava lamp and a digital camera? I believe it was for some e-commerce server they were selling at one time.
Actually, this is convection, too.
In the lava lamp the convection is driven by a temperature gradient. Since the two fluids have a different thermal expansivity, which fluid's density is greater changes as a function of temperature.
In this case, the bubbles have the same density and bouyancy, but different sized bubbles have different ratios of drag force to inertia. Therefore for some bubbles drag carries them along with the bulk motion of the fluid, while for others the bouyancy causes them to rise regardless.
I just found out the other day. I wanted Iced Tea (Nestea Lemon Iced Tea Mix), and I wanted to stir it fast, so I used a blender.
Oddest thing, those bubbles falling like that. They were falling just like the Guinness bubbles.
--Colbey
Guiness Unified Theory - GUT ---------------------------- At the beginning of the Universe, there was Guiness, and there was a bubble. The bubble, unable to resist the temptation to go up, did so. Once it reached the top, it had to come down, so it did. T+2s: There is Guiness, and there is a bubble, going up and down. The other bubbles, realising that this bubble was breaking the state of equilibrium, decided to join it, in it is endless monotonous cycle. T+3s: There is a Guiness, and there are bubbles. The bubbles are in a state of equilibrium. Is this, the future of the universe ? T+300s: A guy comes along, and sees a Guiness, and he sees bubbles. He is fascinated by the bubbles going up and down. He is so fascinated, he decides to create the rest of the universe, the stars, the planets, the comets, and other celestial objects. T+5Days: The guy is still fascinated by the Guiness, and its bubbles. He finds nothing so interesting in the rest of the universe he has created, so he puts plants and animals, on some planets. T+6Days: There is the Guiness, and there are the bubbles, and there is the rest of the universe. Still, the Guiness, with its bubbles, is more interesting. The guy ponders, while watching the bubbles go up and bubbles go down, and decides to put intelligent being, in the form of himself, on of the planets. He calls that being 'Man'. T+6.5Days: There is a Guiness, and there are bubbles, there is the rest of the universe, and there is Man. The first guy, gets a bit thirsty. He looks at the Guiness, and unable to resist the temtation drinks it. T+7Days: There is no Guiness, and there are no bubbles, but there are stars, planest, moons and, then there is Man. The first guy, the guy who has been there from the beginning of universe, and who is now totally drunk, looks at the man, and, he feels that the man looks too happy, and content. Then, he creates a woman.
People spent money on this? It's always been obvious to me that each pint of Guinness represents a full-fledged microclimate, with convection and all. I'm surprised thunderstorms don't break out in it.
Actually, thunderstorms have been know to break out in my head after drinking a large amount of it, but I don't think that counts.
Heck, even I could have done this research. It would have been fun, too. I wonder how the effect changes as the level of stout in the glass drops...
- -Josh Turiel
-- Josh Turiel
"2. Do not eat iPod Shuffle."
I love those little nitrogen widgets they put in them. It is nitrogen that makes the 'small bubbles' required for the creamy head and the downward flow (as the article points out, the bubbles must be less than than 0.05 mm for this).
But the widgets themselves are a truly cool piece of engineering. They hold the nitrogen under pressure until the can is opened and then inject the gas into the beer through a hole so small it almost has to have been drilled by a laser.
The first time I took a Guiness can apart was documented by my girlfriend on her Web Journal. We did some interesting web searchs for more information on the thing. Turns out the widget is patented, and only one of several versions of the same (all of which are patented). Apparently there was a fairly significant research effort by competing companies to re-create the correct creamy foam on canned stout.
I think I speak for all of us when I say "Thanks! It was money well spent!"
Jack
- -
Are you an SF Fan? Are you a Tru-Fan?
starring:
obi wan kenobi: a bottle of guiness.
luke skywalker: mark hamill.
luke: no, my father wasn't a bottle of zima, he was a can of budweiser!
obi wan: that's what your uncle told you, he didn't hold with your fathers full flavor and smooth texture. thought he should have stayed in the vat and fermented longer. which reminds me, i have something for you. your father wanted you to have it when you were old enough, but your uncle wouldn't allow it. thought you might drink old obi wan and pass out in your own vomit.
obi wan hands luke a large pretzel.
luke: how did my father die?
obi wan: a young man named busch, who was a brewer until he turned to evil, opened your father and let him sit for a week. busch was seduced by the dark side of alcohol.
luke: alcohol?
obi wan: alcohol is what gives a beer his power. it's a chemical created by the fermentation process that surrounds us and penetrates us and binds us together.
luke gets a glazed look on his face, like suddenly has the urge to get roaring drunk.
thank you.
fat-time!!
After all, we're the country that figured out how to split the atom trying to put bubbles in beer :)
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
Sorting things according to size? If they can be suspended in a dense enough fluid, like Guiness, larger things will float to the top while the smaller objects cannot help but be carried away by the fluid flow.
Now if you actually mixed this method with some sort of incremental generative process, then things that sink will eventually get larger, while the objects floating on the top can be scooped up for usage! Sorta wacky way of how snow is actually generated in our atmosphere; the wind keeps the water/ice/snow fragments suspended until they get too large or heavy and proceed to fall down.
Just one idea
-AS
-AS
*Pikachu*
$5 / month hosted VPS on linux = awesome!
Alcohol is one of the few things (besides water) that permeates the stomach lining and enters the blood stream without going through the intestines. It's also one of the few things that'll permeate the blood-brain barrier and enter the brain without assistance. The humorous post that you responded to was quite correct in leaving out the bowels (albeit while leaving out the blood stream).
"If one is really a superior person, the fact is likely to leak out without too much assistance" -- John Andrew Holmes
When I was a kid, I used to make "fake beer" by (carefully!) making Iced Tea Mix with either Sprite or Ginger Ale (Canada Dry, naturally).
Tastes good, looks like lager, lots of sugar into your system.
Geez, I think i should try making some with vodka one of these days...:)
PS you don't use a blender for this, it will explode! Just stir carefully...
Pope
It doesn't mean much now, it's built for the future.
Since the air you're already breathing (presumably) is 70% nitrogen, and you don't talk squeaky (at least, no-one I know does), then I fail to see how you reached that particular conclusion. I think you have it confused with helium...
BTW, there's no fridge built for the commercial market that could get low enough temperatures to liquify nitrogen (-176C?).
Wonder if temperature enters into it. Australian's are reknowned for not enjoying their beer in any state but cold.
:)
Sign outside a bar in the backwaters of Indonesia (where Australian back-packers were often encountered
"Yes, we serve fucking cold beer!"
:)
I left my body to science, but I'm afraid they've turned it down...
1) Fluid rises, under influence of all the rising bubbles.
2) Fluid actually goes DOWN at the edges of the glass.. forming a kind of convection-like current (but it's not convection, of course.. just looks roughly similar)
3) The *small* bubbles are carried downwards at the edges of the glass, in this current. Only the small ones.. not the big ones.
Now.. this may make little sense, but remember, the presence of bubbles also causes the density of the fluid to go *WAY* down (detonating a mine underneath a battleship can cause the ship to snap in half.. simply because of the air bubbles produced underneat the ship... the remove the buoyancy and overstress the hull...)
Guinness mixes "soured" beer in with its import draught at about 3% v/v. Souring is accomplished by inoculating a beer wort with lactobacillus bacteria, or, for those of us who don't have access to a microbiology lab AND who live in an area with a high airborne concentration of lactob's (such as Dublin), letting the wort sit open for a few days. Incidentally, this is why it is a bitch and a half for a homebrewer to "copy" Guinness. Thus, a possible reason for the unique behavior of Guinness bubbles is the different solvation environment accorded by the lactic acid produced by the bacteria. However, as any chemist worth his bathtub knows, carbon dioxide reacts with water to form carbonic acid (especially under pressure!), although the equlibrium for the reaction lies strongly with CO2. Who knows... the only other beer that I know of that contains lactic acid (other than my local zymurgist's frequently foul-tasting disasters) is Belgian lambic. It may be interesting to compare the bubble dynamics of Guinness with lambic, though prohibitively expensive if you live in America... decent lambic goes for $7-$12 a 12 oz. bottle, if you're lucky enough to find it stateside.
Okay. The 'widget' in the can of guinness.. here goes.
Guinness is brewed iwth a 75/25 mix of N2/CO2 (You know.. Nitrogen gas/Carbon Dioxide). CO2 apparently creates much more pressure when compared to dissolved Nitrogen... anyway...
When the publician pours you a draught guinness, usually the guinness is passed through a filter with a few tiny pinholes in it.. this causes the beer passing through it to release it's nitrogen en masse, and causes that nice creamy head we all know and love.
Now.. many say the 'widget' in guinness contains compressed gas, and releases that gas when the can is opened... but they, having had a few already, forget that beer (like water) doesn't compress really... and could not possibly hold a compressed widget closed... what really happens is this.
The widget is a plastic container with a few very tiny pinholes laser-drilled into it. This is put in the can, the can is filled most of the way up with guinness, and a drop of liquid nitrogen is placed in the can, and then it is immediately sealed. As the liquid nitrogen turns to gas, the gas is absorbed into the beer, and also increases the pressure on the beer (by increasing the gas volume in the available space) causing liquid to be forced into the widget through those little pinholes.... under pressure. Now.. when the can is opened, some of the beer vacates the little widget, and by moving through these pinholes, acts similar to the bartenders filter, and causes more of the 75/25 n2/co2 mix to be released.. giving a nice, creamy head with strange properties.
'The Workmans Friend - Flann O'Brien/Myles na gCopaleen
When things go wrong and will not come right,
Though you do the best you can,
When life looks black as the hour of night -
A PINT OF PLAIN IS YOUR ONLY MAN.
When money's tight and hard to get
And your horse has also ran,
When all you have is a heap of debt -
A PINT OF PLAIN IS YOUR ONLY MAN.
When health is bad and your heart feels strange,
And your face is pale and wan,
When doctors say you need a change,
A PINT OF PLAIN IS YOUR ONLY MAN.
When food is scarce and your larder bare
And no rashers grease your pan,
When hunger grows as your meals are rare -
A PINT OF PLAIN IS YOUR ONLY MAN.
In time of trouble and lousey strife,
You have still got a darlint plan
You still can turn to a brighter life -
A PINT OF PLAIN IS YOUR ONLY MAN.
The last line of the article reads :
Guinness is made by British-based Diageo Plc.
And all along I thought that Guinness was made by Guinness... Shhh...
I used to have a sig but I left it on a bus
This is why I love Slashdot. Right here.
I could bet the house a pint that none of you had a straight face when you added your helpful tidbit about convection-like currents and N2/CO2 ratios, and I'd win.
On a serious note, I know at least fifty people who could stand to get up from their VDTs long enough to amble down to O'{whatever}'s and tip one back, preferably not alone.
Here's to you guys...you made me laugh, and that's a blessing that goes way underappreciated, way too often. Thanks.
_____
_____
The antidote to bad speech is not censorship, but more speech.
I believe he is. I remember something about this - digitizing pictures of a lava lamp and using them as seed values for random number generation. Apparently, lava lamps are really, really random.
Ah - found the link. Try looking here.
I agree with your sentiments.
Before you moderate this as redundant, please at least do me the courtesy of reading all that I have to say.
Lately, there's been a BIG kerfuffle in Australia with Telstra and their monopoly on broadband Internet access. On a more global scale, Governments everywhere have been declaring that violent computer games promote real life violence - something that most of us disagree with.
I submitted two stories to Slashdot about it - at different stages in the battle against Telstra's ridiculously high prices, and have just submitted a story about the Australian Goverment actually getting something right and declaring the computer games DON'T create homocidal maniacs (since Australia's 'net censorship, and the way goverments all over the world have been blaming computer games for violent crimes), and I'm going to be very surprised if it makes it to the front page as a news item.
And yet a story about someone wasting money on discovering why bubbles in Guinness seem to sink has been deemed to be "News for Nerds. Stuff that matters."
Slashdot's standards are definately falling - I know it's been mentioned before, and people who have said so have been moderated down through the floor - but it's a sad day when news about bubbles in beer moving in unexpected directions is deemed to matter more than news about monopolies and their effect on freedom of access to the Internet, and the fact that at least somewhere in this crazy world a government has realised that playing Quake doesn't immediately turn you into a weapon of mass destruction.
Like the other posts on this matter, this one will probably get moderated down to ridiculous depths as well - but I feel that this needs to be said, and I'm willing to risk my karma to give it a +2 head start before it vanishes into the ether.
Funny, though. I can never manage to watch them for very long. *burp*
And the brethren went away edified.
Please, let me take a moment of your time to recommend the less gassy members of the esteemed Guinness family.
Draught Guinness (from the pub) is very nice, and all, but I never felt the DraughtFlow(TM) cans quite reached the same standard.
... so I drink Guinness Original, which you can get in cans or bottles, and which has a subtly different, more irony taste, without the creaminess. You can sometimes buy Guinness original in bottles in the pub, in which case you might be lucky enough to get the unpasteurised version. Yum.
Alternatively, there's the gorgeous Guinness Foreign Export. In the last century (heh, the century before that, I s'pose) beer for export had to be brewed a little bit stronger, so it survived the long sea journey (hence India Pale Ale). Guinness Foreign Export is 7.5% alcohol by volume, and it's like drinking Marmite. Class in a glass (bottle) -- if you can get hold of it.
--
Guiness is one of those very rare items:
a complete food. It contains, in trace amounts, all the minerals, vitamins, protein and carbohydrate that you need.
However, in order to get enough of everything, a man of average size would need to drink 47 pints a day. But here's the catch: somehow I doubt you would stay an at an average size on this diet.
http://rareformnewmedia.com/
It would seem that this story is on it's way.
"I have a good idea why it's hard to verify programs. They're usually wrong." --Manuel Blum, FOCS 94
After all, they're on the other side of the planet -- so wouldn't things that sink on this side rise in Australia?
Does anyone have a few dozen pints of Guiness (the good English brew, not the bastardized version they export!) to give away for an experiment which will reveal the One Truth of Beer?
Be careful how you respond,
This post encoded with ROT26. If you can read it, you've violated the DMCA. Handcuffs please, sergeant.
No, 'strue! Guinness contains lots of iron, which led to doctors prescribing it to pregnant women a few decades ago.
That's not *quite* true. It was prescribed to nursing women (i.e. after they had given birth).
I travelled to Ireland. I went to Dublin. I went to the Guinness factory and had a beer. I was in heaven.
I travelled around the rest of Ireland. Drank only Guinness. Love love love.
I came back to the states. I drank a Guinness....
PTOOOOIIEEEE!!!
Guinness in the USA sucks.
Actually, I have to say that the bubbles are 'harder' and the taste is more bitter in non-IRL Guinness. How about a study on that?
--
Never hit your grandmother with a shovel, for it leaves a bad impression on her mind...
OK. We now know about Guiness, how about the Corona and lime affect?
For those who don't know what am typing about, take a bottle of Corona and put it in your freezer. Remove the bottle before the beer freezes (we just want the beer to be really cold) and squeeze a little lime in it.
What happens next is really cool. The beer will start to freeze from top down, forming some really neat crystals on the way.
"Guinness is unique in having those mystical falling bubbles"
I wouldn't say that it's unique. Lots of other Irish stouts and ales have the same effect. Lots of English bitters (ales) do it too: try pouring a can of Boddingtons.
"Every loser worth his Stein knows that Guinnes is pressurized with nitrogen instead of carbon dioxide"
Hmmm, are all of those others stouts and ales that I've seen doing it pressurised with N2 when on tap? ie. is it unique to just N2 powered drinks?
I spoke with some marketing people from Guinness at a friend's wedding in the summer. It seems that they now have a widget in their bottles too. Unfortunately a couple of them exploded, so they haven't yet been able to release them!
BTW, why does everybody here use knifes and things like that to open their Guinness cans? It's only thin metal: grab at both ends and rotate back and forth in opposite directions. It will soon tear open without needing much effort. Then again, maybe it's better to use something else as that leads to sharp edges that could slice open your hands as you twist the can!
On a semi-related issue, your glass has to be dirty for the bubbles to really kick in. If you have a clean-room grade glass, the CO2 has no particles to fixate on. It's very similar to the crystallization of solutions needing a 'seed' to start.
---
As a part time brewmeister, I wish to point out that this phenomenon can be replicated with any other beer. The important factor is that Guiness uses nitrogen instead of carbon dioxide. Nitrogen gas has a higher surface tension, hence the smaller bubbles are carried with the liquid flow. On occasion, I and other brewers carbonate with nitrogen and use it for dispensing. I can even make a pale ale emulate the Guiness effect. Nitrogen is more expensive than CO2 though.
Bottoms Up.
So long and thanks for all the fish . . . !!!
This is getting a bit off topic, but what the hell :)
:) sells in low quantities to individuals. A simple tap handle is about $30, and the Guinness-slow-thingy is about $100. You can usually get them from homebrew shops as well, but they all tend to buy from superior and double or triple the price anyway :)
I have a three-tap refridgerator for my homebrew, and I need to get arround to a fourth tap for the nitrogen mix for my stouts.
Superior Manufacturing (I think; it's superior something
The expensive part is the CO2 cannister, but buy big; it will save you in the long term--filling a 20 lb cannister costs about a dollar more than a 5lb. On the other hand, it's not convenient to haul around . . .
"Hmmm, are all of those others stouts and ales that I've seen doing it pressurised with N2 when on tap? ie. is it unique to just N2 powered drinks?
I have only seen Guinness and Boddington's on N2 taps here in the states. I believe I saw others when I was in London, but I forget which ones. Possibky one of the Fuller's, but that would only be a guess.
-d9
In about 1993, the US bottled version was changed for the worse--much worse. It was seriously watered, and I don't know what else.
On the other hand, some yeast slipped through, and a friend cultured it, but I think my sample went bad years ago . . .
Also, before ordering it on tap, check how long the keg's been open. Somewhere around three days seems to be the cutoff . . .
Do you really think that anyone who contributed to quantum mechanics was sober at the time?
And then there's the coswine function from inebriated mathemeticians. Sine is from the unit cirecle, the hyperbolic sine from the unit hyerbola, and they'd had enough that they started working with the unit square . . .
Hmmm. Having known many a bartender in the past, I can assure you that they have no N2 bottle in the back pressurizing the kegs. The bubbles are made very small mostly due to the long rubbery thing that is at the very end of the tap. Inside that little tube is a set of screens, similar to aerators on kitchen taps. These screens make the bubbles smaller than North American beers, which don't have the special tap. So, if you have a relatively viscous beer (such as most stouts), you can give your homebrew the cascade (as most folks call it) by pouring the brew through a set of screens. Of course, you need to have a certain amount of pressure at the screens, so a funnel with a hose connected should be used to gravity feed the spout holding the screens. Incidentally, this setup can be used to add beautiful art to the head of the pint. Now that is a rare skill these days that this beer drinker truly appreciates!
So, I would recommend using 3 to 5 0.05mm screens about 3mm apart, i.e. not touching so that the beer will flow properly. Then most of the bubbles will be of the correct size to cascade. Some will agglomerate, initiating the effect. I haven't tried it, so some experimentation with the number spacing and size of the screens as well as the amount of gravity potential will be necessary. I'm going to try it, and if I succeed, then I will try to get my results posted for all to use!
About the widget - I suspect that that thing simply creates really small bubbles. I intend to check this hypothesis over the next week or so as well.
About the study - I don't think that it really provided new insights, as I have known about the screens well before this study even began. I was told by someone who had known it for years. I suspect that the folks at Guiness have known it for decades. Still, to see it scientifically demonstrated in such a way will silence many a self-proclaimed beer scholar! The most important discovery in my opinion is the size of the bubble requuired for the cascade.
One final observation - the argument that N2 sinks while CO2 rises makes no sense. CO2 is heavier (1.977 g/l) than N2 (1.2506 g/l), so if either sinks, it would be the CO2 before the N2. Of course, being a gas, they both are significantly more bouyant than the Guiness... I have heard this argument vehemently debated over many a pint of the world's finest stout.