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DO too high - help troubleshooting

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  • DO too high - help troubleshooting

    Hi all. Ive been running into issues with DO levels lately that I'm finding hard to trace back. 10bbl brewery. We've been canning with a mobile canner for over a year now and our very first few runs the DO levels in the tank were spectacular (10-15ppb). The last couple of runs theyve been in the 65-90 range. The last batch oxidized at these levels (NE style) and we had to recall and dump. Carb levels were also a little high so that didnt help package either as draft held up ok. These beers were also brite transferred. I co2 fill the receiving tank up to 14 psi, purge, fill up again to 10 psi, purge, fill to 6 psi and start the slow transfer with just co2. Have done this for about 6 months without noticing any other oxidation issues (but no DO numbers to back that up, but draft or cans havent noticeably changed).

    We just had a run where we decided not to brite transfer 3/4 beers we were canning thinking the transfer is where we picked up oxygen. DO levels in the tank were still 65, 70, 78 and 88 ppb respectively, with the 70ppb beer being the one we actually transferred (as well as had the dry hop port open for a decent bit with positive co2 pressure while adding 8 bags of fruit puree). Shaken DO in the cans ranged from 145-240. The other 3 beers we dry hopped on day 4 for a couple days, soft crashed to 58 degrees and dosed in a second dry hop charge. Being very cognizant of oxygen from the last run, on the second dry hop i filled the headspace to about 8 psi, purged, did that again, purged, and then opened the dry hop port with continuous positive co2 pressure while dropping in 2, 11lb bags that were opened for the first time during that dry hop. Closed up the port and purged maybe another 2-3 times and then opened the blow off valve back up to the bucket and left it sit for a couple more days before crashing.

    Im starting to go crazy thinking about how it could be so high. Early on we were dry hopping earlier in fermentation (day 2 and 3) but not all beers were necessarily done that way. But i can see how those DO levels can be lower. Is there a bigger flaw that anyone else notices here that I'm missing? I find it hard to believe that with these processes, im picking up that much oxygen dry hopping after fermentation. Havent noticed any leaks and head pressure in all 4 tanks remained constant for about a week before packaging. I've even started questioning the purity of our co2. Is that even a possibility?

    As a result, we are about to get a DO meter of our own. Does anyone have any recommendations? Or a link to a good, and somewhat recent, thread about DO meters? Would be looking in the 10-12k price range. Thanks for all the help in advance.
    Jay
    Southern Swells Brewing
    Jacksonville Beach, FL

  • #2
    Theres a few places you have overlooked. First, your pumps, bad seals, loose clamps on the suction side will allow air to be drawn in during transfers. The same goes for hoses, with fast moving beer, they can draw in air through bad clamping around the ferrule. As for Oxygen in your cans, that is likely due to the canning line itself if you have good beer in your brite tank prior to canning.

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    • #3
      Jay,

      You do need a DO meter, and it's something you will use daily in multiple locations once you have it, as part of your QC.

      When we got one, I thought that our procedures were pretty good and we'd use it to dial in our new rotary bottling line. I was wrong. We found so many problems before the beer even reached the bottling line, that significantly raised our DO levels. Here is a small list of some things we changed:

      1. We began capping off FVs and putting CO2 pressure on around day 5 or 6
      2. We began transferring or filtering with a CO2 balance hose between the brite tank and fermenter.
      3. We started cleaning brites with acid under CO2 pressure, only opening them for a hot caustic wash after 5-6 turns.
      4. We purge the brites now using the DO meter to measure the off gas at the CIP arm, trying to get it under 50 or so. That time takes a lot longer than you would think.
      5. We keep the dosing tank on the DE filter under a constant blanket of CO2 being injected in the side, with a lid over the opening.
      6. We daily check DO at the filter, in the brite after filtering, at the filler going into the bowl, and then shaken bottles during packaging.

      You can't just look for leaks either. One day, the beer after the bottling line pump spiked up in DO, but the beer in the brite tank was fine. We couldn't see any leaks at the pump, but decided to change the pump seal anyway. It looked fine, but changing the seal dropped the DO way back down. Same with the dosing pump seals on the filter. They can look fine, not be leaking, and still be pulling in oxygen and spiking up the DO.
      Linus Hall
      Yazoo Brewing
      Nashville, TN
      www.yazoobrew.com

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      • #4
        Originally posted by lhall View Post
        Jay,

        You do need a DO meter, and it's something you will use daily in multiple locations once you have it, as part of your QC.

        When we got one, I thought that our procedures were pretty good and we'd use it to dial in our new rotary bottling line. I was wrong. We found so many problems before the beer even reached the bottling line, that significantly raised our DO levels. Here is a small list of some things we changed:

        1. We began capping off FVs and putting CO2 pressure on around day 5 or 6
        2. We began transferring or filtering with a CO2 balance hose between the brite tank and fermenter.
        3. We started cleaning brites with acid under CO2 pressure, only opening them for a hot caustic wash after 5-6 turns.
        4. We purge the brites now using the DO meter to measure the off gas at the CIP arm, trying to get it under 50 or so. That time takes a lot longer than you would think.
        5. We keep the dosing tank on the DE filter under a constant blanket of CO2 being injected in the side, with a lid over the opening.
        6. We daily check DO at the filter, in the brite after filtering, at the filler going into the bowl, and then shaken bottles during packaging.

        You can't just look for leaks either. One day, the beer after the bottling line pump spiked up in DO, but the beer in the brite tank was fine. We couldn't see any leaks at the pump, but decided to change the pump seal anyway. It looked fine, but changing the seal dropped the DO way back down. Same with the dosing pump seals on the filter. They can look fine, not be leaking, and still be pulling in oxygen and spiking up the DO.
        Thanks a lot Linus. That does give me some additional things to think about and yes, we are looking to order a DO meter by the end of the week. What do you guys do for dry hopping on IPA's? I have a sneaking suspicion thats where we are picking it up despite the amount of co2 purging before, during and after the dry hop is complete. We dont use any pumps once the beer is in the fermenter, although the same concepts would still apply with gaskets on the hoses and block and bleed setup. We push everything with co2 but most recently, we kept everything in the unitank and still picked up DO in the 60-90 range.We're also going to break down all of our tanks and start looking for cracked gaskets since its been a couple years now and havent ever looked at any of the static pieces that dont get broken down for each cleaning cycle (PRV, blow off/cip arms at the top of the tanks, etc.).
        Last edited by jsvarney5; 01-16-2019, 06:33 PM.
        Jay
        Southern Swells Brewing
        Jacksonville Beach, FL

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        • #5
          Use CO2 to protect the beer from O2.

          If you have high levels of dissolved co2 in the beer when you transfer, when the pressure inevitably drops the co2 breaks out and stops oxygen dissolving in. Try spunding during the second half of fermentation to let the pressure build up. When you dry hop you can let the headspace pressure off first and then drop the hops in. There will be lots of co2 breakout when the hops hit the beer to scrub away any oxygen that comes with the hops. This means there needs to be plenty of headspace in the tank or you could get a beer fountain. Then lock up the fv again to keep the pressure up.


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          • #6
            If you still have yeast around while you are dry hopping, they will mop up any oxygen that comes in so long as you are flowing CO2 into the tank headspace while adding the hops. We have never had issues with it, our IPA that are heavily hopped usually have DO around 10ppb, a few times it was off the scale low for the meter.

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            • #7
              Originally posted by jebzter View Post
              If you still have yeast around while you are dry hopping, they will mop up any oxygen that comes in so long as you are flowing CO2 into the tank headspace while adding the hops. We have never had issues with it, our IPA that are heavily hopped usually have DO around 10ppb, a few times it was off the scale low for the meter.
              Thanks jebzter. Earlier on i was doing most of the dry hopping during fermentation and had DO numbers in the 10-15 range. But in efforts to reduce some hop bite, and also have the ability to harvest yeast, Id really like to be able to dry hop after fermentation and with a soft crash. When dry hopped this beer, I soft crashed, dropped yeast, set the head pressure to 10, purged, did this again, purged and then dry hopped with 20 psi continuous positive co2 pressure while the port was open, closed it up, pressured up to 10 again 2 more times with purging and then left the blow off valve open to the blow off bucket. So with this process, is it really feasible that I'm picking up 60-90ppb DO?

              For what its worth too, I really enjoy the beers so far that have been dry hopped this way. They were just packaged so no noteworthy oxidized characteristics but I'm concerned for what might be coming. So i'd really love to be able to dry hop this way and keep my DO number down at the same time.
              Jay
              Southern Swells Brewing
              Jacksonville Beach, FL

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              • #8
                We dont fermentation hop, we crash to below 60, harvest yeast, dump the remainder and then dry hop. But even at temps between 40 and 60, there will still be some yeast in suspension that will mop up most oxygen that comes in with a dry hop under positive pressure.

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                • #9
                  As stated earlier, bung the FV towards the end of fermentation, then bleed that off and dry hop. When you put the hops in, leave the blow off open, and only close once you have sealed the top up (it will blow off like crazy, and if you aren't quick enough, foam). leave the tank under pressure rather than opening back up to blow off bucket.

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                  • #10
                    Originally posted by Fossie View Post
                    As stated earlier, bung the FV towards the end of fermentation, then bleed that off and dry hop. When you put the hops in, leave the blow off open, and only close once you have sealed the top up (it will blow off like crazy, and if you aren't quick enough, foam). leave the tank under pressure rather than opening back up to blow off bucket.
                    Dont do that, never bung something thats going to be dry hopped. It will end in a mess unless you have a hop cannon or some way of introducing the hops under pressure. All you need to do to create the CO2 flush is to hook up a line to the blowoff and have it flowing while adding the hops.

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                    • #11
                      What Linus said!!!

                      Buy a good DO meter and use it often! I'm amazed that people are buying filtration and packaging equipment for hundreds of thousands of dollars and won't spend $10k on a DO meter. I'd be a ten spot that you're getting DO all over the place. Agree with L on everything...plus it takes us 6 HOURS of constant purging to get our 120 barrel BBT down below 50ppb.

                      good on you for asking!
                      Larry Horwitz

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                      • #12
                        Which DO meter do you guys recommend?


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                        • #13
                          Originally posted by Mattieu View Post
                          Which DO meter do you guys recommend?


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                          We use the Anton-Paar Cbox. It is only useful for filtered beer. You just have to think of hops and it will get clogged!

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                          • #14
                            Meters

                            Hamilton Beverly (measures PPM and PPB), or the Hach 3100 are both vis meters and are good places to start. BTW, call a 3rd party leasing company and finance that bad boy if you can't come up with the case all at once. The CBox is great...but it's a fortune and as noted won't do wort at all, or unfiltered beer well.
                            Larry Horwitz

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                            • #15
                              Thanks - I’ll look into this financing idea. We are just starting her in France. Investment is high so I can’t go back to our banker.
                              So lease or - if we are lucky with that grant from the region - we can swing it...
                              thanks again


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