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  • Oxygenating Wort.

    We're experiencing a few slow fermentations and have been advised that we should try adding oxygen pre yeast dosing. Any advice on dosing levels (mg/litre), should we increase the dosage with more viscous worts or does it remain the same etc etc? We have a 20 brl plant in deepest darkest Hampshire (the old one) so we're a bit thick in the sticks. Infact any advice would most gratefully received. All the best,

  • #2
    I'm a bit confused, what is your process from kettle to fermenter now? Are you saying you are not oxygenating at all? When and how is the yeast pitched?
    Jeff Byrne

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    • #3
      Martin,

      If you're not already oxygenating/aerating before yeast pitching, I would aim at a total of 10-15mg/litre of O2 initially.

      Ideally it would be useful to know what levels you have already - there must be some to get a reasonable degree of fermentation, even if these are slow at times.

      You can then adjust the guideline figure, above, to best suit, based on your current O2 levels.

      Hope that helps!

      Comment


      • #4
        Our brewpub here doesn't have the resources to calculate the precise mg/l, but we run an aeration stone inline between the chiller and the fermenter. we set the O2 flow at 2-2.5 Bar and that seems to work fine for us.
        Just my $0.02. Hope it helps, even if just as a baseline.
        -Lyle C. Brown
        Brewer
        Camelot Brewing Co.

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        • #5
          flowrate

          We run ~2.5 liters/min using a medical flow rate regulator into an oxygenation stone inline to the fermenter. This has worked great for us.

          Cheers,
          Steve

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          • #6
            Originally posted by kramling
            We run ~2.5 liters/min using a medical flow rate regulator into an oxygenation stone inline to the fermenter. This has worked great for us.

            Cheers,
            Steve
            Is it 2.5 liters, or 2.5 Bar? I am going from memory, as I am not at the brewery during the day (2 jobs), but we have a medical regulator, and I thought it was calibrated in Bar.
            -Lyle C. Brown
            Brewer
            Camelot Brewing Co.

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            • #7
              flow meter

              It is a oxygen flow meter and it runs in liters/min. I said regulator but meant flow meter.

              Cheers,
              Steve

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              • #8
                I'll have to take a look when I get to the brewery this afternoon, and see if that is what we have.
                -Lyle C. Brown
                Brewer
                Camelot Brewing Co.

                Comment


                • #9
                  I think that having control of oxygen is the next most important part of reliable fermentations right after temperature control. For years I just eyeballed the oxygen in a sightglass but once I could gauge the oxygen, I noted more consistent and on-target fermentations- more significantly than I would have guessed.
                  I use between 2 and 3 scfh (57 to 85 l/hr) of oxygen, but that number is only relevant when it is compared to my wort cooling rate of about 12 gallons/minute (3.4 l/min).
                  This www.mcmaster.com/#5079k24/=5o95za flowmeter is eminently affordable and will make you happy.

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                  • #10
                    Pressure vs flow

                    Bar is a unit of pressure roughly equal to one atmosphere or 14.7 psi. It says nothing about how much oxygen you're putting into your wort; you can have two bars of pressure on your aeration stone with zero flow. A rotameter is an inexpensive way to measure flow rate, but as Moonlight said, you have to relate this flow to the flow of wort. The old-school rule-of-thumb is one part per million oxygen per degree Plato. This corresponds with recommendation from KWLSD of 10-15 mg O2/liter wort. Personally, I use air instead of oxygen for all standard worts. You can't overdose with air, so you don't need a flow meter. It's much cheaper, too. I understand that oxygen can be overdosed and "burn" your beer. Also note that with dried yeasts, most manufacturers recommend that you DON'T aerate your wort on the first pitch.
                    Last edited by gitchegumee; 02-04-2010, 07:17 PM.
                    Phillip Kelm--Palau Brewing Company Manager--

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                    • #11
                      This all sounds like good science, but your wort will only absorb x amount of dissolvable o2 at any given temp, the rest blows off. I say, O2 the crap out of your wort and it will take off. Have you tried using olive oil as a yeast nutrient?

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                      • #12
                        Visceral Brewing

                        I'm a little reluctant to tell that I've always done it by sight; via a sight glass attached immediately downstream of the air stone. Almost always get a good, active fermentation with our house ale yeast on our 10bbl system.

                        Prost!
                        Dave
                        Glacier Brewing Company
                        406-883-2595
                        info@glacierbrewing.com

                        "who said what now?"

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                        • #13
                          Originally posted by Capt. Bob
                          This all sounds like good science, but your wort will only absorb x amount of dissolvable o2 at any given temp, the rest blows off. I say, O2 the crap out of your wort and it will take off. Have you tried using olive oil as a yeast nutrient?
                          Good advice if you're using air (~20% O2), but if you're using pure O2 you can in fact overoxygenate your wort. Yeast, depending on the strain, will require anything in the range of 4-14 ppm O2. Wort at 15C (59F) saturated with air will have approximately 8 ppm of O2, whereas wort at the same temperature saturated with pure O2 could have upwards of 40 ppm dissolved O2.

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                          • #14
                            Where does everyone get their oxygenation and/or aeration assemblies from? I have one for my 15 gallon pilot system, but I'm not sure where to get one for a 3.52 bbl system. Any insight would be apreciated.

                            cheers
                            beejay


                            EDIT:

                            I found the "Inline Micro-Oxygenation System 1-1/2"" from GW Kent for $350. Is this similar to what everyone else is using, and is it a good price?
                            Last edited by beejay; 02-06-2010, 01:21 PM.
                            Beejay
                            Pipeworks Brewing Company

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                            • #15
                              Oxygen supply, a calibrated mass-flow meter,a non-return valve and a few yards of 1/4" O.D. stainless tubing...more or less!

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