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Minimizing O2 Uptake - dry hopping and tank transfers

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  • Minimizing O2 Uptake - dry hopping and tank transfers

    What special procedures are people following to minimize oxygen ingress during transfer to an empty tank as well as dry hopping?

    We currently do not have a DO meter so we are pressurizing and purging our brite several times before filling with beer. Because we are half filling the brite usually (or less) any concentration of oxygen in the head space could do even more damage than if it were more full.

    As for the dry hop - we are currently popping open the 4in hop port in the top of our ferms and dumping in the hops as quick as we can from a food grade bucket and replacing the lid as quickly as we can while on a ladder.


    The reason I ask is that I occasionally get a slightly oxidized flavor in our beers even when fresh. This usually involves a dry hopped beer, but not always. Another data point is that I have never observed it in a beer we processed 100% in a unitank. Therefore I am looking at dryhop and tank transfer/brite purging procedures!


    Thanks!


    Brian

  • #2
    There's a recent thread on using a converted keg to force dry hops into a vessel as a slurry. You can flush the whole keg with CO2 to scrub out most of the O2, fill the keg with beer, and push the whole thing back into the tank with pressure. Haven't tried it, but it's a good idea.

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    • #3
      Yes, the above. It is always a good idea to purge your tank with CO2 (I do it twice) before you allow beer in. Also, if you are getting Oxygenation problems, I would consider trying Brewtan B. I'm only now experimenting with it, but it is supposed to cut down on oxygenation. -- In my case I'm looking for added freshness with longer-term storage in a warmer cellar.

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      • #4
        Originally posted by briangaylor View Post
        What special procedures are people following to minimize oxygen ingress during transfer to an empty tank as well as dry hopping?

        We currently do not have a DO meter so we are pressurizing and purging our brite several times before filling with beer. Because we are half filling the brite usually (or less) any concentration of oxygen in the head space could do even more damage than if it were more full.

        As for the dry hop - we are currently popping open the 4in hop port in the top of our ferms and dumping in the hops as quick as we can from a food grade bucket and replacing the lid as quickly as we can while on a ladder.


        The reason I ask is that I occasionally get a slightly oxidized flavor in our beers even when fresh. This usually involves a dry hopped beer, but not always. Another data point is that I have never observed it in a beer we processed 100% in a unitank. Therefore I am looking at dryhop and tank transfer/brite purging procedures!


        Thanks!


        Brian
        Hi Brian,

        Are you using an orifice plate at the bottom of your brites when purging with CO2? If not, I would recommend getting one.

        Secondly, I suggest using silicone gaskets on all your tanks. They create a much better seal then the standard gaskets.

        Try running CO2 through the CIP arm when dry hopping through the top port. Push only at 2psi or so but make sure you have a way to vent out the pressure of the tank on top before opening the 4in dry hop port. We put a butterfly valve right before the PRV. Take the PRV off with the valve closed and then open the butterfly valve to vent off the pressure. You should see a decrease in DO this way.

        Overall the best thing you can though is to get a DO meter, they are an extreme game changer. Best of luck.

        Pat
        Brewer
        Castle Danger Brewery

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        • #5
          Originally posted by briangaylor View Post

          We currently do not have a DO meter so we are pressurizing and purging our brite several times before filling with beer. Because we are half filling the brite usually (or less) any concentration of oxygen in the head space could do even more damage than if it were more full.
          The best way to fully purge a tank with co2 is to completely fill it with liquid then push all of that liquid out with co2. That being said, cleaning your brights closed and under pressure in between uses will help you maintain a complete purge and also save you money on co2.

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          • #6
            Don't defeat your PRV....

            Putting a valve in front of a PRV defeats (in the eyes of the law) the safety of a PRV. Use a dry-hopping port, or some other penetration. But never put a valve in front of a PRV. Safety first!
            Phillip Kelm--Palau Brewing Company Manager--

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            • #7
              If you have a tank you can burn, one method I've used for dry hopping is to run a CIP cycle on a fermenter or bright tank. After your sani cycle, drop your hops into the bottom of the tank, then do a CO2 purge. After your purge, pressurize and xfer into the tank racking through the hops. We never saw any DO problems.

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              • #8
                Keep green beer under light top pressure to avoid O2

                According to Jean De Clerck, beer saturated with CO2 won't pick up oxygen (Textbook on Brewing, vol. 1 p401). Try locking your fermenters down in the last stage of fermentation to allow top pressure to build up. At transfer to conditioning tank, the slight pressure drop will cause a small amount of co2 breakout and this will scrub any O2 out.

                Where I'm working now, we set a spunding valve to 1 bar and lock the fermenter down when about 50% attenuation is reached and allow the pressure to build up. The conditioning tank/what passes for a BBT is prepurged with CO2 before transfer. We do have a DO meter and wait until an air sample from the tank sample port (low down) gives a reading of less than 0.1mg/l dissolved oxygen. Then we pump over from FV to CT. The donor tank pressure is 1bar (at the start), the receiving tank is 0.4-0.5. DO values in the CT after the transfer are usually <0.01mg/l

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