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  • DO levels

    What levels of DO in finished beer are normal/acceptable?
    __
    Kushal Hall
    Common Space Brewery
    Hawthorne, CA

  • #2
    My definitive answer...

    It depends.

    More directly, it depends on package type, the capabilities of your system to prevent O2 ingress, and the style of beer (some of them really need some oxidation). There may be more factors that I'm missing, but these are the big ones that are coming to mind right now.

    I find the second parameter to be the most restrictive. You can try to have a QC parameter of less than 1 ppb, but if your system can't get it down there, then you're wasting your time and dumping all of your beer.

    It seems to me that you should calibrate your system first with what it currently allows for O2 ingress, then identify and address your O2 hotspots as you find them. It's tough to mentally map all of the problem areas right off of the bat.

    Once you're there, then you're good to start identifying parameters for DO levels.

    Sorry I couldn't be more direct help.

    Bill

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    • #3
      That's all fine and dandy but the question was "what's normal?"

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      • #4
        i like to see bright tank levels below 10 ppb and packaged beer (bottles/cans) below 30 ppb.

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        • #5
          DO2 became a real focus in the industry a good few years ago with companies like A-B, who's style of beer is very oxygen-sensitive.

          As Bill said, the lowest level you can achieve is the level you need to aim for; a 'robust' beer will be far more DO2 resistant (ie. noticeable oxidised taste). For anything other than the very lightest flavours, most beers can cope easily with 30ppb or so.

          A good, reliable meter and some time spent checking your plant will result in locating areas where you are picking-up DO2. Pumps, centrifuges, joints, etc. are all common areas.

          Don't forget, too, it takes only a little oxygen leaking in to make a big difference and it is very possible to have air getting in but no sign of beer leaking out at the same point.

          You will soon be down to levels chaser has - which are excellent, btw!

          All a big change from when I first joined the industry and we had DO2 specs of 0.75PPM for bottled/canned beer and 1.00PPM for keg...

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          • #6
            THANKS good to have a starting point.
            Any suggestions on brands/types of DO meters?
            I am thinking something that I can easily put into a triclover attachment would give me the most flexibility to test along different points in filtration and packaging.
            __
            Kushal Hall
            Common Space Brewery
            Hawthorne, CA

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            • #7
              Thanks kwlsd. I've been able to significantly reduce DO levels by going through the process you and bill mentioned of just checking the DO levels at every point in the process and making changes from there. It was sometimes frustrating constantly changing cold side procedures but there was always a sense of accomplishment watching the numbers drop.

              I've mostly used the membrane type orbisphere. I took readings off sample ports if they were there, and if I wanted one off a TC fitting I would just put a sample port onto it and hook the DO meter up to it. For bottles/cans you will need a piercer. I've also used the optical DO meters for taking readings off wort or fermenting beer as the membranes get trashed quick if you use them with wort.

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              • #8
                Yes, it's oddly satisfying to find one of those persistent but hidden sources of oxygen ingress, isn't it?

                The membrane, eg. Orbisphere, meter is a great unit. Easy to use and easy to look after, plus calibration is straightforward as it uses air (free!) as a standard.

                For wort, or other areas where the meter is exposed to high DO2 levels, we advise using the '58' or '52' membrane rather than a '56'. These have a higher upper level and any loss in low-end response isn't relevant at high levels.

                The protection cap and grille should prevent physical damage to the membrane.

                We have also supplied a number of piercers, together with a robust protocol for analysing freshly-filled packages to look at good practice in bottle/can filling.

                For optical systems, the Haffmans instrument is good to use. They make two versions - one for low level (<2ppm) and one for high level (up to 20ppm).

                Still, the membrane/EC sensor can do the whole range in one...
                Last edited by TL Services; 09-21-2011, 01:04 AM.

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                • #9
                  just a bump here.


                  i like to see bright tank levels below 10 ppb and packaged beer (bottles/cans) below 30 ppb.
                  Everyone agreeing with Chaser here as to a baseline level of acceptable O2?


                  Thanks.
                  __
                  Kushal Hall
                  Common Space Brewery
                  Hawthorne, CA

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                  • #10
                    If you can achieve those levels consistently then you will certainly have no DO2 problems!

                    One proviso though: Low levels in finished beer are one thing, but make sure you don't have high levels earlier in the process (except at the start of fermentation, naturally!).

                    I've known people ignore high DO2 levels in conditioning because "it will go down given time", not appreciating that the only reason for that reduction over time is the beer is oxidising...

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                    • #11
                      100 ppb or less in packaged beer is probably a good level if you are selling locally and moving product quickly. I really prefer seeing them below 50 though, and typically they are at 30-40 for us.

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                      • #12
                        We use a digital gehaltemeter from Haffman's, which are a bit on the pricey side, but you can also use them for other things such as carbonation levels in brite tanks and packaged product.

                        I would agree that below 10 ppb brite tank and 30 ppb packaged is acceptable.

                        If you want a good lab reference, buy a 6-pack of A-B beer and compare your's to their's.

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                        • #13
                          Originally posted by paintz55
                          If you want a good lab reference, buy a 6-pack of A-B beer and compare your's to their's.
                          Hmmm...a difficulty with this is that by the time you buy it, the beer will have been packaged for some time so will have oxidised; so the DO2 level you would see is not necessarily true to what is was when first packaged.

                          However, the figures of 10ppb in tank and 30ppb in package are very good! In fact they are excellent...for a well-flavored beer then 30ppb in tank would not cause any noticeable defects.

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