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  • oxygen in final product

    I have a short shelf life on my packaged product because of disolved oxygen. I pasturise srtaight after bottling, 60c for 10 mins, this doesnt alter the flavour to much but the beer only last for about 2 mnths before you can start tasting the oxygen.
    I think that the oxygen is comeing from the filling process, the machine used to be pre--evac but they have taken that side of things away & it only blasts a dose of co2 from the bowl pressure to pressurise the bottle, I dont think it is enough what do you lot rekon about my problem.
    thanks.
    ps if John hinterdink is reading please contact bintara brewery.
    MIKE S

  • #2
    Mike---Are you testing your DO's before the filler ? You can have the best filler on the market, but if your beer has high dissolved oxygen levels in the bright tank and you package it..........Something to check.

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    • #3
      Agree whole heartedly with Fred's comment.

      If you are not pre evacuating the bottle, then the blast of CO2 really needs to vent directly to atmosphere, not merely pressurise the bottle, or vent back into the bowl. If you vent back into the bowl, you are likley to have a very high oxygen content in the CO2 above the bowl, thus you will be replacing the air in bottle with a mix of air and CO2. You therefore need to vent off prodigious amounts of CO2 from the bowl to control the oxygen level in the bowl.

      If you can take a few bottles off immediately after purging, but before filling, seal them quickly (cork or wine bottle "Instant reseal") and check the residual air in the bottle by absorbing the CO2 with caustic, keeping the bottle neck under water.

      Finally, after jetting and crowning the bottle, check the bubbles in the neck. You should only have very fine bubbles. Bubbles larger than those you get when you pour a beer in a glass are indicative of residual air, not CO2 in the headspace.

      Ideally you look to reinstate the pre-evacuation, but....

      Cheers
      dick

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      • #4
        I would agree with the other postings. If you're unsure of your bottled air levels and your DO's the pasteurization could really be damaging your beer. Essentially your speeding up the whole aging/oxidation process. The good news is that if your filler used to have pre-vac you should be able to make this adjustment with ease and buy the necessary QA equipment to monitor bottle fills. Investment in shelf life is an investment in the brand.
        Mike Jordan
        Brewmaster
        Boxing Cat Brewery
        Shanghai, P.R. China
        michael@boxingcatbrewery.com

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        • #5
          I dont have acess to DOs testing , I pretty sure that the oxygen is happening in the machine.
          I dont understand the cuastic idea well can you explain it in a bit more detail?
          Will purging the bottles with co2 before they go on the filler be an improvement?
          There will be no chance of the owner folking out for the pre-evac to be installed, bummer.
          Not sure how to fix the problem.
          MIKE S

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          • #6
            If there was Dos in the bright tank wouldnt it show in our keged product?
            It doesnt seem to be, they deffinatly taste better on tap than in the bottle.
            MIKE S

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            • #7
              Yes it would show up, but pasteurisation makes the chemical reactions producing the staling compounds much faster, so staling becomes noticeable far earlier. I suspect the filler/crowner systems are the main cause of your problem though
              dick

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