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Soda fizz-out

  1. Feb 15, 2008 #1

    jim mcnamara

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    Q: Does tapping on the top of sealed aluminum fizzy soda cans (like diet coke for example)
    reduce the probability of "explosive fizz out" - where soda fizz-out goes onto the floor, your socks, etc.

    Assuming that tapping the can top several times does have an effect (I do not know this to be true) the only explanation I can come up with:

    tapping removes any [tex]CO_2[/tex] bubbles on the side surface of the can. These bubbles act as condensation nuclei.

    Anybody know something about this? Am I all wet? not soda-wet... :smile:

    Everyone here assures me that can tapping works. I dunno.
  2. jcsd
  3. Feb 15, 2008 #2


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    I never tap on cans and since they were invented, I've had some spew due to being dropped, but I don't think any amount of tapping would have helped. I have had more bottles, both glass and plastic spew than cans, however I've never heard any claims of tapping on the bottle cap as a means of preventing spewing.

    Of course I can't convince my youngest daughter of this, she always taps on cans before she opens them. Even though we both open our cans and neither spew, she is convinced that her tapping made a difference. :biggrin:
  4. Feb 15, 2008 #3


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    As far as I know, the only thing tapping does is delay the time from when the can drops out of the vending machine until you open it, which can give the bubbles a chance to settle before you open it to avoid it fizzing over.
  5. Feb 15, 2008 #4
  6. Feb 15, 2008 #5
    Hey Evo, maybe you and your daughter could shake the cans a bit before trying the tapping step?


    According this guy, shaking the can promotes the formation of small bubbles which serve as nucleation sites for the formation of bigger bubbles when you open the can. At the point where you'd open the can, I think most of the small "starter bubbles" would still be in solution (and not adhering to the wall of the container), so I don't think that tapping the can would do much to the bubbles in solution.

    So maybe a more interesting question is: how long should you wait before opening a pop can which has been shaken?
  7. Feb 15, 2008 #6


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    I would pay absolutely anything to see Evo (with or without daughter) shaking her cans. Even more if I can take pictures.
  8. Feb 15, 2008 #7
    I dunno about that, I think its just the elapsed time. A cool trick: take a soda can, and with a pen, press right on the line of the opening and keep pressing. When it goes it sounds about like a loud firecracker or a .22. It's pretty cool. Ha ha, leave it to Danger to find your spelling/grammar errors (or not in this case, but still...) and exploit them for his entertainment. Good one man
    Last edited: Feb 15, 2008
  9. Feb 15, 2008 #8


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    Thank you too much. I aim to disgust. :biggrin:
  10. Feb 15, 2008 #9


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    Well I know I'm going to have trouble getting to sleep tonight...
  11. Feb 15, 2008 #10
    I had always thought that much of the danger of fizz-out is caused by there being too much pressure in the can. It seems like if there's too drastic a change in the pressure when it's opened it increases the tendency of the carbon dioxide to, uh, precipitate or nucleate, or whatever the correct term is. So shaking the can up makes a fizz-out more likely but so does something like transporting a can that was filled and sealed at sea level up to Denver, Colorado.

    My trick is to turn the cap or crack the tab until you just barely start to hear a hiss, then leave it until it stops hissing. That lets the pressure be released slowly.
  12. Feb 15, 2008 #11


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    That is exactly what I do with my beers, which are frequently pressurized due to me running from the wife with them in my pocket. :biggrin:

    Just kidding. She can drink me under the table any day. If I could convince her to do anything else for me under the table, I would be a happy man.

    By the bye, that mention of Denver reminded me of something that might be of interest to anyone who has wondered about it. That little hole in the cap of various cosmetic products such as shaving cream or antiperspirant... it's a vent to prevent the cap from blowing off with a lowering of ambient pressure. It's one of those great ideas that looks really stupid until you know why it was done.
  13. Feb 15, 2008 #12
    Actually Quasar, there's generally fairly local bottlers. If I'm catching it right and you live in Denver, I think there's a bottling plant in ABQ. So that might supply Denver, unless theres one in Denver. I think there is like a Pepsi (quite small) factory in Durang(e)o.
  14. Feb 15, 2008 #13


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    I assumed that tapping the can shook off any bubbles stuck to the inside of the lid. It would be that liquid that spewed out when the pressure was released. No bubbles stuck to the lid, no spray.
  15. Feb 16, 2008 #14
    No, I live on the East Coast. I'm was speaking hypothetically, if someone brought something bottled on the East Coast on a car trip to Denver. Or if something was bottled at a very low temperature and warmed to a high temperature before it was opened.

    I'm sure that the bottlers understand these things and compensate for them in various ways, like keeping the temperature constant and maybe even bottling under negative pressure. (Assuming I'm right about what causes the fizz-out.)

    I can see you've never experience major fizz-out, Dave! It's all fun and games until someone loses an eye. You can lose half the contents if you encounter major, I'm talking catastrophic, fizz-out. :wink:
  16. Feb 16, 2008 #15


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    Driving from Louisiana to Colorado Springs with pop in the cooler has almost no effect on the pop. The pressure difference between the inside of the can and outside at sea level is about 183 inHg. The pressure difference between sea level and Colorado Springs at 6000 ft is about 6 inHg, meaning the pressure difference between the inside and outside has increased by about 3%. (The effect on things with a lower pressure differential, like bags of potato chips, plastic mustard bottles, or soccer balls, is much more dramatic whether we're travelling up in elevation or down in elevation.)

    Tapping on the side or top of the can just gives you something to do while the bubbles settle on a shaken can. The better option is to open the can slowly in the sink or at least point the can away from you.

    One thing I'm sure of. The old trick of spinning an egg to see if it's boiled or raw doesn't work when you try to apply it to a game of Beer Hunter to see which can is the shaken up one.
    Last edited: Feb 16, 2008
  17. Feb 16, 2008 #16


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    I also presumed it didn't work on major blowout.
  18. Feb 16, 2008 #17
    OK, I thought it may have been an example. Denver gets all the attention. I think they may even be lower elevation than were I am.
  19. Feb 16, 2008 #18
    I like the idea of the dropping causing small bubbles to form on the sides of the cans, which act as nucleation sites for more Co2 to come out of the liquid. Tapping on the can would be enough to dislodge these bubbles and they'd float harmlessly to the top, decreasing the nucleation sites.

    But is that true? Does pop fizz more if poured into a glass with a rough interior (jagged) compared to a smooth interior? Seems like it should.
  20. Feb 16, 2008 #19
    Also, soda cans have a thin plastic membrane on the inside that should keep bubbles from nucleating.
  21. Feb 17, 2008 #20

    jim mcnamara

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    Denver is 5200. As long as you are not along the Rio Grande, and are North of ABQ you are higher than that. I lived near the bottom of La Bajada for years; it was 5500.
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