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Carbon Dioxide quality and impact on dissolved oxygen in beer

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  • Carbon Dioxide quality and impact on dissolved oxygen in beer

    I am trying to understand how co2 used in force carbonation impacts the amount of dissolved oxygen in beer.

    Our local supplier (in Belgium) provides CO2 grade 3.0 which is considered food grade. The specs:

    CO2 > 99.9 vol.%
    H20 < 10 vol.ppm.
    O2 < 200 ppm
    N2 < 800 ppm

    Calculating the percent of o2 it looks like it is 0.02%.

    According to this paper by Hach (who manufacture DO meters) the industry standard for DO in final package product is 40-150 ppb. They have a table which states that with an o2 impurity of 0.02% the added DO to the beer is between 142-567ppb. This puts me several times over the limit.

    Does this mean the CO2 I am buying is not suitable for carbonating beer? Note that I am struggling with the shelf life of my beers presumably due to oxidation and I am trying to understand whether the CO2 I am using could be a possible culprit.

    I appreciate if anyone could share their CO2 spec sheets so I can understand what the O2 ppm levels others are using.

    Any experience here would be appreciated.

  • #2
    Apparently there is a spec / guideline for beverage grade co2:



    Or



    Which state that the allowable o2 impurity is max 30ppm.

    Is this what everyone is using? Or is anyone working successfully with lower grades such as what I am using?

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    • #3
      ISBT standards for beverage grade CO2: https://www.google.com/url?sa=t&rct=...26130881,d.cGc

      O2--30ppm or less.
      Timm Turrentine

      Brewerywright,
      Terminal Gravity Brewing,
      Enterprise. Oregon.

      Comment


      • #4
        Originally posted by TGTimm View Post
        ISBT standards for beverage grade CO2: https://www.google.com/url?sa=t&rct=...26130881,d.cGc

        O2--30ppm or less.
        30 ppm? That is horrific! That has to be ppb.....

        Chris

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        • #5
          Originally posted by cbaugh67 View Post
          30 ppm? That is horrific! That has to be ppb.....

          Chris
          No that’s correct. The special lab grade stuff is down to 2 ppm, but it’s pricey. Am using that on my small test batches, kegs are tasting fresh even after 6 months.

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          • #6
            Don't forget that oxygen is much less soluble than CO2. I'm not up on partial pressure calculations, but in very high levels of CO2, you will get virtually n oxygen dissolving. If you think that oxygen forming circa 19 % of the volume of air, circa 190,000 ppm will only dissolve 8 - 10 ppm in water / wort, dependent on temperature mainly, if you start of at only 30 ppm, you are not going to get much dissolving. Assuming (probably incorrectly) the same ratio dissolves, you would dissolve less than 2 ppb from CO2.
            dick

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            • #7
              Originally posted by dick murton View Post
              Don't forget that oxygen is much less soluble than CO2. I'm not up on partial pressure calculations, but in very high levels of CO2, you will get virtually n oxygen dissolving. If you think that oxygen forming circa 19 % of the volume of air, circa 190,000 ppm will only dissolve 8 - 10 ppm in water / wort, dependent on temperature mainly, if you start of at only 30 ppm, you are not going to get much dissolving. Assuming (probably incorrectly) the same ratio dissolves, you would dissolve less than 2 ppb from CO2.
              Yeah, that is a great point. I was just taken aback a bit. But after thinking about it, those are the calculations that I need to do. Thanks for reminding me. I've been out of school far too long.....

              Chris

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