Common misconceptions about Vacu-vin (Don't use one for beer!)

Discussion in 'General Beer Topics' started by domtronzero, Oct 22, 2013.

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  1. domtronzero

    domtronzero

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    I posted this on BA some time ago.

    I don't think anybody ever put much thought into this, but I was hoping to help clear the air for future beer drinkers (only those that'll actually read this though, I guess).

    Prerequisite knowledge:
    CO2 in solution is a function of the partial pressure of CO2 above the solution - Henry's Law - not a function of the partial pressure of any other gas above it. Earth's atmosphere is only a tiny fraction of CO2 (0.039%) and therefore, the partial pressure of CO2 in air in the bottle is negligibly reduced when using a vacuum sealer. Therefore, it doesn't actually "pull" any CO2 out of suspension. It does, however, remove a good portion of oxygen out of the headspace, reducing the amount of oxidation that happens in the bottle.

    The real issue is this:
    The vacuum sealers are a one-way check valve. They allow a pressure to be reduced on one side of the apparatus (within the bottle). However, with carbonated beverages, once the CO2 starts coming out of suspension to fill the headspace, the pressure inside the bottle increases to a level slightly over atmospheric conditions, the check-valve allows that pressure to be purged through the valve, and out of the bottle. I made this dandy little pic using AutoCAD to explain (you'll probably have to open it in a new tab to read the small text below the bottles):

    [​IMG]

    A simple stopper keeps the pressure inside and does not allow the beer to become flat just like a vacuum stopper, but since there is no check valve, the simple stopper will keep the carbonation in suspension until there is enough pressure to blow the stopper out of the neck (which has happened to me a few times). The vacuum sealer will simply open and purge the excess pressure, and reduce the amount of CO2 in suspension in your beer.

    tl;dr: vacuum stoppers bad, simple wine stoppers good.

    In summation:
    1. A vacuum sealer WILL NOT pull a noticeable amount of CO2 out of solution (by means of Henry's Law).
    2. A vacuum sealer will still make your beer go flat due to the check-valve mechanical nature.
    ___________________________________
    Another point of interest:

    Q: What is the pressure that the check-valve opens at?
    A: I don't know exactly, but it really isn't too much. I've played with one and have blown air through it (holding it up to my mouth) and it wasn't difficult to get it to open up. Human lungs can really only exert about 2 psi of pressure (this was an experiment we did a long time ago in college where we blew into a U-tube filled with water and measured the height difference).

    With the average beer containing 2-3 volumes of CO2 dissolved in solution, there could be a pressure of at least 1 atmosphere above atmospheric. At serving temperature (38F) I have to keep my kegs at about 12-17 psi to achieve 2.5-3 volumes of CO2 in solution, with 30 psi required to maintain 4.5 volumes for my sours. This is a substantially large amount of pressure exerted in bottles. This is why most sours and Belgian beers are bottled in thick champagne-style bottles that can withstand that amount of pressure.

    Therefore, the pressure in your average bottle of beer is much more than enough to open the check-valve on the vacu-vin.
     
  2. stakem

    stakem

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    This seems like a ridiculous amount of info/technical data for something that is painfully obvious...

    Am I missing something?
     
  3. domtronzero

    domtronzero

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    Sorry, you don't have to read it (and I'm assuming you didn't). It's not painfully obvious. Go look on the other sites about how many people rave about Vacu-vin stopper systems. Seriously. People think they're the shit and they're not.
     
  4. FTowne

    FTowne

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    The real question is, why on earth would anyone legitimately need to re-seal a beer?
     
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  5. stupac2

    stupac2

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    I have a lot of friends who are super excited about BCBCS being in 12-ounce bottles this year because they can't take down a 22 themselves. I call them pansies.
     
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  6. stakem

    stakem

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    I glanced it over, posted my comment and then read it in it's entirety.
    I am still facepalming that people think this is a wise investment for beer.

    tl;dr - we the people of BT are not the "tools" on the other sites
    GOD damnit we are the elite.

    'murica
     
  7. domtronzero

    domtronzero

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    For the most part I bottleshare with one other guy. That's it. A 2-man tasting team. We like to open a ton of bottles and put down a bunch of different beers in a single sitting (we also like blending beers and other shit I'm sure you'll all chastise me for). When we open bottles we typically drink about half of them in one sitting, then revisit them later on in the evening if we're getting drunk and don't want to continue opening bottles.

    Oftentimes, my girlfriend works late and can't make it to the shares before all the beer is gone. I will reseal bottles of "special" stuff and put them in the fridge for her to drink when she gets home from work. She appreciates it, and it makes me feel good about myself.

    But who am I kidding. Queue the mouth breathers and their battle hymn, "DRINK THE WHOLE DAMN BOTTLE IN ONE SITTING, PANSY!!!"
     
  8. stakem

    stakem

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    Real talk

    I sometimes like to solo 4 or more bombers on any given week night. Sometimes I like to dabble across the board and drink a glass of one, then another before returning back to #1. Its my way of tricking my palate into thinking im drinking something different even though I drank it 3 glasses ago. I just put the original cap back on the bottle and in the event I backfat the bottle is ready to go when I wake up.
     
  9. FTowne

    FTowne

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    If you use a large opening bottle opener and don't destroy the cap, you can reuse the original cap and the beer will be fine for 6-8 hours.

    edit: I use this one all the time and the cap stays perfectly in shape.
    [​IMG]
     
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  10. domtronzero

    domtronzero

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    Yah I know. But I have these super cheap plastic wine stoppers that are used for the homebrew competition that I run and it's convenient.

    I didn't want this to turn into a thread where everyone bashes each other because they choose to drink beer differently than others. I'm an engineer and I like scientific stuff. I had fun "researching" this topic and learned some great stuff in the process. I wanted to share it with other science-minded people (they're is a surprisingly large population of them that are involved here and involved with beer in general).
     
  11. FTowne

    FTowne

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    All good. Engineers gonna engineer.
     
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  12. Billy Brux

    Billy Brux

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    Now you are obligated to verify your claims with controlled experiments and quantify how much CO2 is actually lost over time.
     
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  13. domtronzero

    domtronzero

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    I'll need a grant from the AHA to do this experiment.
     
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  14. Rempo

    Rempo

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    I like this. I will refer to 12-ounce bottles as pansies as well. "Gonna mow down that row of pansies."
     
  15. 1v1willwreku

    1v1willwreku

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    "I'm going to sneak in and sniff those pansies so hard."




    so close
     
  16. quirkzoo

    quirkzoo

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  17. domtronzero

    domtronzero

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  18. Previously

    Previously

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    Next time I come over, I'm going to be wearing pansies in my hair. So hippie.

    [​IMG]
     
  19. MordorMongo

    MordorMongo

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    Bunch of fucking pansies.


    I approve.
     
  20. Billy Brux

    Billy Brux

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    Can't drink the whole beer? Drain pour that chit, ya cheapskate!

    I prefer this to "drink it, ya pansy" because cheapskate is less derogatory than pansy and I don't like to encourage overconsumption.
     
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