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  • Dissolved oxygen measurement

    Hello everyone,
    You have any idea,how to measure the concentration of oxygen in wort without any DO meter ?
    There are one Titrimetric method named A Winkler titration,but i think it is not suit to beer.

  • #2
    lots of people have a flow rate L/m that they measure and then calculate expected DO based on L/m and amount of time transferred.
    Your prob not going to get any really accurate results without a DO meter

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    • #3
      Just get yourself a decent suitable oxygen meter.

      Many years ago, when I started in the brewing industry, oxygen meters were just being developed. I was asked to cross check the results of the meter against a colour produced by injecting dye into beer. It was a real pain in the backside, and only rarely did I get what I considered a sensible result. It only occasionally worked with pale beers, such as lagers, but was such a pain to get a genuinely uncontaminated sample that we gave up on it and accepted that the results it gave were sensible, if not necessarily totally true, but were quicker and far more accurate than I could ever obtain from a colour reaction.

      In other words, don't even go there. It really isn't worth the time and money, as all you will be doing is wating both. Just splash out on a suitable oxygen meter, and maintenance spares, not one of these cheap and chearful whole ppm meters used in the water industry. Get yourself a proper instrument for measuring ppm levels of oxygen in beer etc. There are plenty of discussions on this site about suitable oxygen meters.
      dick

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      • #4
        I'm not sure if anyone uses them here but YSI made the best DO monitoring equipment when I used to work for a water quality monitoring agency

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        • #5
          Originally posted by dick murton View Post
          Many years ago, when I started in the brewing industry, oxygen meters were just being developed. I was asked to cross check the results of the meter against a colour produced by injecting dye into beer.
          DCI, perhaps? (= dichlorophenol-indophenol)

          Anyways...I couldn't agree more about getting a decent DO meter!

          The benefit of choosing the right one means you can use one meter to cover most of the critical sample points - wort, post-fermentation, transfers, etc. Certainly you should avoid the cheap, water-industry type meter as these just don't have the resolution for accurate low-level measurement.

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          • #6
            Originally posted by TL Services View Post
            The benefit of choosing the right one means you can use one meter to cover most of the critical sample points - wort, post-fermentation, transfers, etc.
            Any suggestions on particular models? From what I've seen, it seems like you need separate meters for wort production (ppm) and packaging (ppb). Are there any out there that do both well?
            Sent from my Microsoft Bob

            Beer is like porn. You can buy it, but it's more fun to make your own.
            seanterrill.com/category/brewing | twomilebrewing.com

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            • #7
              there are lots, but I DO NOT recommend the Dr. Thiedig DOX meter. It may have been great 30 years ago, but I have found it to be delicate and difficult to keep calibrated. Also, it gives widely differing results depending on how it is (and I am) feeling.

              To give you an idea of how finicky this thing is, it seems to work best when facing east.

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              • #8
                OK - recommendations

                Personally I have used Orbisphere (Hach) optical and electrochemical sensors with great success, and Centec, Haffmans and Mettler Toledo optical units.

                I suggest you get whoever is going to be based most locally and can give you the best backup service. You should be able to get secondhand EC sensors, but probably not the optical units yet as they are still fairly new to the industry.
                dick

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                • #9
                  Originally posted by a10t2 View Post
                  Any suggestions on particular models? From what I've seen, it seems like you need separate meters for wort production (ppm) and packaging (ppb). Are there any out there that do both well?
                  Orbisphere, Haffmans & Mettler tend to be the industry 'standards', which means there is a lot of experience out there with their instruments.

                  Electrochemical sensors have a wider operating range than optical units (currently, at least) so would be my suggested choice for someone looking for a good workhorse to cover the brewing process from end to end. A major benefit of EC is that, with the correct choice of membrane, it is possible to have a working range from over 20ppm (more than enough for wort oxygenation) to ppb levels that would be seen in final product.

                  In that situation, a meter like the Orbisphere 3650 would be a good choice, or possibly the Mettler InTap4000e.

                  Hope that helps!

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                  • #10
                    Originally posted by Junkyard View Post
                    lots of people have a flow rate L/m that they measure and then calculate expected DO based on L/m and amount of time transferred.
                    Your prob not going to get any really accurate results without a DO meter
                    What is the best way to go about this? Is the a formula given the size of my O2 stone, size and length of hose, time transferred, and psi / L/m of oxygen I use? What if I use a regulator that measures in PSI?

                    Thanks for any suggestions.

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                    • #11
                      22.4 litres oxygen at STP (zero C, atmospheric pressure) contains 32 grams oxygen (one mole)

                      Therefore you can work out what flow rate of oxygen at what pressure is required to achieve (x) ppm oxygen at whatever your wort flow rate is.

                      One litre of wort = 1,000,000 mg for practical purposes because it is normally expressed as weight oxgygen / volume of wort not weight of wort.

                      So if you want 8 ppm, then you need 8 mg per litre of wort.

                      The temperature of the wort and oxygen makes very little difference in actual flow rate, but if you want to be really accurate P1 * V1 / T1 = P2 * V2 / T2, where the values for 1 are at STP, and the values for 2 are at real life temperatures.

                      Have fun with Excel!!
                      dick

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