from the whether-tis-nobler-to-tap-or-not-to-tap dept.
Tech Review reports on some Danish experiments on beer foaming, https://www.technologyreview.com/s/614907/does-tapping-the-bottom-of-a-beer-can-really-stop-it-fizzing-over/ (likely also available on archive.is if you don't subscribe).
Among the great questions in science, one stands sadly neglected: Is it possible to stop a shaken beer can from foaming by tapping it before opening?
There are good theoretical reasons to think this should work. The tapping should release any bubbles that are stuck to the inside walls of the can. These should then float to the surface and dissipate, making the beer less likely to foam when it is opened. But is this true?
Today, we get an answer thanks to the selfless work of Elizaveta Sopina at the University of Southern Denmark and a few colleagues. This group has tested the theory for the first time using randomized controlled trials involving 1,000 cans of lager. And luckily for the research team, the result raises at least as many questions as it answers, ensuring a strong future for beer-related research.
[...] The cans were then shaken using a "Unimax 2010 shaker" for two minutes at 440 rpm. "Pilot testing revealed that this shaking method successfully mimicked carrying beer on a bicycle for 10 minutes—a common way of transporting beer in Denmark," says Sopina and co. Unwanted foaming must be at epidemic levels there.
The researchers then weighed each can, tapped it by flicking it three times on its side with a finger, and then opened it. Finally, they weighed the can again to determine the amount of beer that had been lost.
The results are palate tickling. Sopina and co compared the amount of beer lost for tapped and untapped cans that had been shaken and found no statistical difference—both lost about 3.5 grams of liquid to foaming.
They also found no meaningful difference between the cans that had not been shaken—when opened, they lost about 0.5 grams on average.
Personally, I don't have a dog in this fight, always drink bottled (or tap) beer. But for you can users I suggest that looking inside the can might be a more direct way to see what is going on with the bubbles--seal up a can with camera & light source inside, or make some cans with a small viewing window. But that might generate an answer, where the goal of this research seems to be to consume more beer...For Science!
(Score: 2) by Booga1 on Thursday December 12 2019, @01:49PM (7 children)
I have long suspected that the tapping is simply a way to give people something to do for a few more seconds so the foaming goes down a bit. It's just in their heads if people attribute it to the tapping.
(Score: 2) by barbara hudson on Thursday December 12 2019, @02:08PM (3 children)
SoylentNews is social media. Says so right in the slogan. Soylentnews is people, not tech.
(Score: 2) by Booga1 on Thursday December 12 2019, @02:22PM (1 child)
I am referring to the foaming that happens when you open it. I only care what I get out of the can that goes in my face and not on the floor.
(Score: 2) by barbara hudson on Thursday December 12 2019, @04:16PM
SoylentNews is social media. Says so right in the slogan. Soylentnews is people, not tech.
(Score: 3, Funny) by tangomargarine on Thursday December 12 2019, @05:30PM
Back in college we had one of those mini-fridges that technically had a separate freezer compartment, but it wasn't fully sealed between the fridge and freezer. So if you got those little pints of ice cream and wanted them to stay frozen, you had to dial up the coldness setting on the whole thing, basically.
My roommate would store ice cream in there, and I would keep cans of soda cool as well. (Can you guess where this is going...)
Since the temperature of the whole fridge wound up below freezing, but the cans are pressurized, the contents can't freeze because the pressure alters the freezing point. But when you take a can out and open it...
The pressure equalizes, all the water in the soda flash-freezes into a cylindrical block of ice, and the rest of the flavorings and whatnot gets violently ejected from the top of the can.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 1) by maggotbrain on Thursday December 12 2019, @05:02PM (2 children)
My girfriend does this with her cans of soda. Taps lightly three times and opens. She is an Hawaiian native and says that her mother did this and her mother before that.
I consider it a quaint matrilineal, island ritual dating almost as far back as pre-statehood for them.
(Score: 2) by c0lo on Thursday December 12 2019, @09:18PM
Probably a tradition going on for millennia, right?
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 3, Informative) by Magic Oddball on Friday December 13 2019, @09:51AM
I remember some of my friends in high school doing the same thing when opening sodas during lunch, and they were blond Californian girls. I don't think I've ever seen anybody do it otherwise, though.
(Score: 2) by looorg on Thursday December 12 2019, @01:50PM (10 children)
Should be the same issue for soda etc. I dont tap it. Just slowly rotate the can one or two times (top-bottom axis). That always worked in my experience.
(Score: 3, Informative) by The Mighty Buzzard on Thursday December 12 2019, @01:58PM (3 children)
Dunno why that should work either. It's not so much that there are bubbles in the liquid, it's that quite a bit of CO2 has come out of solution. There's really not a whole lot you can do to remedy that except keep the container cold and wait.
My rights don't end where your fear begins.
(Score: 3, Interesting) by FatPhil on Thursday December 12 2019, @02:51PM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 3, Interesting) by looorg on Thursday December 12 2019, @03:37PM (1 child)
I'm not saying that it makes scientific sense in any way shape or form, at least not in a way I can explain. I didn't even come up with the idea to begin with but was told, I tested it and it seemed to work. That said I think the idea is that there is an air-pocket at the top of the can. So if you shake it the bubbling will start. This could be checked by just taking a can, feel it. Then shake the can, feel it again and you should notice that the pressure inside the can is higher. So I would think the idea of rotating the can top-to-bottom-to-top again would be that the air-pocket will change direction as it travels to the bottom then to the top again and perhaps it's just that enough time have passed for it to "calm down" again. At least after doing it I have never had a big soda fountain spew forth as I open the can.
(Score: 1, Interesting) by Anonymous Coward on Thursday December 12 2019, @04:19PM
> Then shake the can, feel it again and you should notice that the pressure inside the can is higher.
Did this experiment in the instrumentation lab I took in the mechanical engineering department. We started with normal Coke cans, polished a bit of the surface and bonded/glued on strain gages* to measure any changes in the strain (stretching/contracting) of the aluminum. The gage becomes one arm (or more, depending on the gage types) of a Wheatstone bridge and tiny changes in strain can be measured. This is a common tool in all kinds of structural testing.
At this point in the experiment, shaking the can had no effect on the gage readout--thus no change in pressure. Made sense to me, since shaking the can does not add or remove any material from the can (or change the volume of the can), but some of my lab partners were expecting a change in pressure.
Then we opened the can to release the pressure (I think we tapped or waited long enough to not make a geyser). The strain gage setup showed material contraction. While I don't recall measuring temperature, a really precise experiment might do this as well--since releasing pressure typically cools things down.
The final step was to cut open the can, measure the thickness of the aluminum at the gage location and calculate the hoop stress reduction from the change in strain--which could then be used to calculate the initial pressure. IIRC, we got about 80 psi (550000 Pa) for our can, but it has been a long time and my memory could be off.
* Yes, "gage" is the spelling that I learned. Here is a link to one of the oldest manufacturers who traditionally use this spelling https://www.micro-measurements.com/stress-analysis-strain-gages [micro-measurements.com]
(Score: 3, Funny) by DannyB on Thursday December 12 2019, @02:26PM (5 children)
For soda I avoid all foaming over by simply asking the waitress for a large picture of diet coke.
The lower I set my standards the more accomplishments I have.
(Score: 0) by Anonymous Coward on Thursday December 12 2019, @02:36PM
Does the picture of diet soda have less foaming than pictures of regular soda?
(Score: 5, Touché) by FatPhil on Thursday December 12 2019, @02:58PM (1 child)
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by DannyB on Thursday December 12 2019, @03:53PM
And the picture doesn't need to be rotated end over end. Which would not be good.
The lower I set my standards the more accomplishments I have.
(Score: 2) by captain normal on Thursday December 12 2019, @05:30PM (1 child)
I don't care for diet coke (nor any soda drink, other than seltzer water), but I do like my beer served in a pitcher. I would imagine it would not be possible to drink an image of a diet coke.
Everyone is entitled to his own opinion, but not to his own facts"- --Daniel Patrick Moynihan--
(Score: 2) by DannyB on Thursday December 12 2019, @08:52PM
Diet coke is probably acidic enough to dissolve any picture into solution. Unless it has a metal frame.
The lower I set my standards the more accomplishments I have.
(Score: 5, Funny) by Snospar on Thursday December 12 2019, @02:04PM (1 child)
I was convinced they were going to suggest looking directly into the can as you open it! You know, like those folk from the Darwin awards who look directly down the barrel of their loaded guns while they clean them.
Huge thanks to all the Soylent volunteers without whom this community (and this post) would not be possible.
(Score: 2) by The Mighty Buzzard on Thursday December 12 2019, @08:43PM
That's most definitely Darwin Award material. Anyone who owns a gun should know you always treat them as if they're loaded unless they are actually disassembled. Pointing a barrel that's not attached to anything at stuff is fine but as soon as you start putting the pieces back together you watch where it's pointed at all times.
My rights don't end where your fear begins.
(Score: 1) by jon3k on Thursday December 12 2019, @02:27PM (6 children)
What a weird thing to say. There are plenty of awful draft beers and plenty of amazing canned beers. I think you probably don't know as much about beer as you think you do.
(Score: 0) by Anonymous Coward on Thursday December 12 2019, @03:42PM (2 children)
> plenty of amazing canned beers
I make no claims to know much about beer, but I normally buy it at Trader Joe's and everything there is in bottles. Thus very little recent experience with cans.
(Score: 0) by Anonymous Coward on Thursday December 12 2019, @08:34PM (1 child)
Don't know where you live, but on the left coast Trader Joe's carries beer in cans as well as bottles.
(Score: 0) by Anonymous Coward on Friday December 13 2019, @05:36AM
Western NY State (which may be different than NY City at the other end of the state). Haven't seen any canned beer in our store that I can remember...but after this exchange I'll look closer.
(Score: 1) by Night Goat on Thursday December 12 2019, @05:48PM (2 children)
(Score: 2) by maxwell demon on Thursday December 12 2019, @07:09PM (1 child)
The last time I drank anything out of a can was last millennium.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 0) by Anonymous Coward on Thursday December 12 2019, @10:43PM
Cans are way better containers compared to bottles for the beer inside. No light and no oxygen transport. Craft breweries have been making the switch over the last decade because of that, but one of the biggest hurdles for them has been the perception, not the technology. It is the same thing that the wine industry has been facing for the last two decades. The better stopper for wine is synthetic cork, and the best stopper is the twist-off. They've had a hell of a time trying to convince the wine snobs that twist-offs are actually much better for the wine (unless you are dealing with a wine that you need oxygen permeation over time to "age" it).
(Score: 3, Insightful) by loic on Thursday December 12 2019, @02:31PM (2 children)
With a 50 cL bottle of soda, in my experience, when you properly tap all around from top to bottom, suddenly the quantity of visible bubbles diminishes significantly. Then you can open it. Not sure it is placebo, as as far as I could observe, it does seem to take a lot more time for CO2 to settle without interaction (10+ minutes) on the bottle than with the tapping method (less than a minute).
(Score: 2) by FatPhil on Thursday December 12 2019, @02:52PM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Thursday December 12 2019, @03:29PM
A shaken can of soda... Tap the TOP of the can for about 10-15 seconds, no loss when opened. I did that all the time. Not tapping it but leaving it alone for 15 seconds results in a shower.
(Score: 2) by All Your Lawn Are Belong To Us on Thursday December 12 2019, @02:54PM (2 children)
You don't tap on the side. You tap it on the top (where the pull tab is).
I can drop, shake, etc. any soda can, spend ten seconds tapping the top of it, and open it without spraying anything. I don't tap and there's a foam overload.
I won't completely discount unknown factors, but I would deny that it's a placebo effect.
So I reject their reality and substitute it with my own.
This sig for rent.
(Score: 2) by All Your Lawn Are Belong To Us on Thursday December 12 2019, @03:30PM
And I forgot to add.... only three times isn't right, either. Remember the words of Zeep Xanflorp, "A crank a day isn't nearly enough! Crank it!"
OK, back to my Gooblebox.
This sig for rent.
(Score: 0) by Anonymous Coward on Thursday December 12 2019, @04:11PM
This has nothing to do with the placebo effect.
(Score: 0) by Anonymous Coward on Thursday December 12 2019, @03:49PM (2 children)
Sure, except NO ONE is going to shake a can of beer for 2 minutes. Tapping stops it from foaming up, but NOT for a beer shaken for that long!
(Score: 0) by Anonymous Coward on Thursday December 12 2019, @08:18PM
From tfa, it seems that SOMEONE does shake their beer that much:
The cans were then shaken using a "Unimax 2010 shaker" for two minutes at 440 rpm. "Pilot testing revealed that this shaking method successfully mimicked carrying beer on a bicycle for 10 minutes—a common way of transporting beer in Denmark,"...
(Score: 0) by Anonymous Coward on Thursday December 12 2019, @11:24PM
I used to shake the fuck out of a can of Meisterbrau before giving one to my wife, but had to stop because that shit smells like donkey piss. And also because she beats the shit out of me when she gets the Meisterbrau golden shower.
(Score: 2) by Pslytely Psycho on Thursday December 12 2019, @09:56PM
So what did they do with all the beer they opened?
If they tossed it would that not constitute Alcohol Abuse?!?
If they drank it however, that might account for their findings and flawed methodology.
Inquiring minds want to know.....
Alex Jones lawyer inspires new TV series: CSI Moron Division.
(Score: 3, Informative) by hendrikboom on Friday December 13 2019, @01:37AM
I just pull the pull tab off very very slowly. And when I start to hear fizzing I stop and wait for it to stop fizzing. That's the CO2 coming out. the open it a little more. Gradually I get the can open without t spraying all over.
I use a similar technique on champagne bottles. Very neat. Except you do have to be ready to hold the cork back at a certain point to prevent everything from exploding outward.
Of course all that stopped when My doctor informed me my pancreas was somewhat calcified and that if I went on drinking I'd die. I only get to do this now when the drink is for someone else.
-- hendrik
(Score: 2) by ElizabethGreene on Friday December 13 2019, @04:47AM (1 child)
Pop drinker here, not beer.
I flick the side of the can to tell if it's overpressurized, i.e. if it's going to spew all over me when I open it. It's a data collection routine, not an attempt to fix it.
(Score: 0) by Anonymous Coward on Friday December 13 2019, @05:41AM
Please let us know what you observe when you flick the side of the can? As noted earlier (strain gage experiment), shaking a sealed Coke can doesn't change the internal pressure.