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  • Bottle airs laboratory testing?

    I've used a Zahm & Nagel package airs tester in the past--still have it--and can't seem to get reliable, repeatable numbers. Anyone know of a lab, preferably in the NW US, where I could send some bottles for airs testing?
    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

  • #2
    Originally posted by TGTimm View Post
    I've used a Zahm & Nagel package airs tester in the past--still have it--and can't seem to get reliable, repeatable numbers. Anyone know of a lab, preferably in the NW US, where I could send some bottles for airs testing?
    It is my understanding that the Zahm air tester does not measure dissolved oxygen. I believe it only measures gas other than co2 in the airspace, and does not account for oxygen bound in solution. This can be a misleading number.

    For a Total Package Oxygen content you will need another device. I'd opt for optical systems, but they are not cheap. Beverly is on the low end, but requires a separate can/bottle piercer.

    Before sending to a lab, I'd suggest asking around. There are a lot of breweries near you and more than a few likely have in house testing of DO. The measurements for TPO should really be taken as soon as possible after packaging for accuracy. Trade for a case of beer and make some friends.

    Otherwise, I believe White Labs might, and probably AlcBevTesting.com are a couple options.

    Comment


    • #3
      Thanks, Unferm.

      Unfortunately, while it might look like there are a lot of breweries around here, the nearest is 4+ hour's drive away--and the nest nearest is 300 miles. We're a little isolated up here between the mountains and the canyons.

      I'm aware of the limitations of the Zahm unit. I've been using it for years, but the biggest problem I have is that I simply don't get repeatable results from it. Airs from a single batch of bottles will be anywhere from none to 2 ccs or more, even from the same head of the bottling machine. This may reflect a problem with the bottler, but I strongly suspect it's the subjectivity of the Zahm tester.

      White Labs would be practical. I'll give them a call.
      Timm Turrentine

      Brewerywright,
      Terminal Gravity Brewing,
      Enterprise. Oregon.

      Comment


      • #4
        Originally posted by TGTimm View Post
        Thanks, Unferm.

        Unfortunately, while it might look like there are a lot of breweries around here, the nearest is 4+ hour's drive away--and the nest nearest is 300 miles. We're a little isolated up here between the mountains and the canyons.

        I'm aware of the limitations of the Zahm unit. I've been using it for years, but the biggest problem I have is that I simply don't get repeatable results from it. Airs from a single batch of bottles will be anywhere from none to 2 ccs or more, even from the same head of the bottling machine. This may reflect a problem with the bottler, but I strongly suspect it's the subjectivity of the Zahm tester.

        White Labs would be practical. I'll give them a call.
        I'd be interested to know if it is an equipment issue. There isn't much to those air testers, so I would think we the brewers are the most variable factor, but you never do know. Did you check your seals and concentration of your solution?

        I assume your bottles from the same batch and head appear to be the same amount of air? What type bottler are you running?

        I saw there was breweries in McCall, Pendelton, Backer City, and Walla Walla (all 1.5hr or less), but I would concede they may not be big enough to have that equipment. Also I don't know your road situations. When I was in Bellingham we had a bridge collapse that turned a 2 hr drive to 5, so I know how it goes.

        You said you've used the Zahm for years, have you always had this issue with repeatability? (been considering one at my recent brewery, but have only used one a handful of times before, interested in your opinion)

        Is the purpose of testing your headspace to check for oxygen issues?

        I only ask because you may see inconsistent results after shipping bottles and having them tested. Personally I would call AclBevTesting and talk to them a bit about it. (and in full disclosure, I previously worked for WL) You should email/call Kara Taylor directly if you want to talk to WL about it.

        Comment


        • #5
          Timm,

          I've been there too. We used a Zahm air tester for years before we bought a reconditioned Orbisphere. Once we had the Orbisphere, we tried to correlate DO levels to the Zahm ml air readings, and couldn't find any correlation. The Zahm will just tell you how much non-CO2 gas was in the headspace.

          Personally, we made so many improvements to our entire process once we got the DO meter, that I wish we had bought the meter years before. We changed all kinds of procedures on transfers, brite tank cleaning, filtering, purging tanks, purging the filler bowl, etc. None of those changes were huge but the cumulative effect was big on improving the shelf life of our beers. One time, we saw a big spike in DO after our bottling line pump. We pulled the seal out and it looked fine, but we replaced it anyway. The DO went from 300 ppb back down to ~10 ppb. We would have never noticed that without the DO meter, and it wouldn't have shown up as headspace air with the Zahm.
          Linus Hall
          Yazoo Brewing
          Nashville, TN
          www.yazoobrew.com

          Comment


          • #6
            Thanks for the replies!

            Unferm: Maps don't show anything about travel in NE Oregon. The only town within 1.5 hour's drive of here is La Grande, which has a start-up brewery. We're surrounded by 10,000' mountains and 3-6,000' canyons.

            The Zahm air tester has too many subjective variables. It's a big piece of fragile, expensive lab glass, partially filled with a concentrated NaOH solution, that you have to shake the bejeezus out of. I've tried it many times over the years, and just never felt I was getting repeatable results, even when testing bottles taken from the same bottling head of our 12-head GAI 3003A Bier within minutes of each other.

            I'll give AlcBev a try later today.

            Linus--I'll look into the Orbisphere. Our budget is pretty well shot for now, but I'd really like to get a better handle on our DO situation. We're not having a crisis or anything, but I suspect a few bottles get out with high DO levels. Never had a problem with anything kegged, fortunately.
            Timm Turrentine

            Brewerywright,
            Terminal Gravity Brewing,
            Enterprise. Oregon.

            Comment


            • #7
              Air vs DO

              The testing of air in bottles is a very different test than is the test for DO. The Zahm and Nagel air tester is looking for the amount of air/oxygen exposure inside a given can or bottle. It can be done weeks or months later and still give you an idea of how well or badly your filler is operating. I have used Zahm and Nagel testers for 30+ years and always found them to be reliable, and to give repeatable results. You do have to make sure that there are no air pockets in the hoses or rubber pieces. The first bottle run should purge out any of these potential air pockets regardless, so you may just want to ignore the first test result. Your scattered results may also be telling you that the filling stations on your filler are not filling the same. The fobbings may be inconsistent, which can lead to very different air levels in bottles.

              The real culprit in the aging of a bottled beer is,of course, dissolved oxygen. Dissolved oxygen, however, will react with the beer in your bottles and disappear. So a DO test on a bottled beer can indicate no problem - when you do have one! The Zahm and Nagel shows you the other atmospheric gases trapped in your bottle. If you have a ml of "gas" in your bottle, you know you have an oxygen problem, even though that gas is mainly nitrogen now.

              The DO test is a wonderful tool. It can pinpoint oxygen pickup problems very exactly. But it has to be done on a very timely basis, before the oxygen reacts with the beer. The DO test is great for identifying air pickups in hoses, pumps, transfers, measuring the aeration at the start of a ferment, etc.

              It can also define problems at the filler. If the testing is done quickly.

              But most of the air problems involved in filling beer will show up in the headspace of a bottle or can, and damage the beer in the upcoming days as the oxygen is absorbed into the beer. The old fashioned Zahm & Nagel type of tester is your best bet for finding problems on a filler. (But get a DO tester for the rest of the brewery!)

              Comment


              • #8
                I figured there was a bit more to the story as far as travel. I have been through the Baker City, Le Grande, Pendleton route a few times, but wasn't sure about Enterprise itself.

                I think that the Total Packaged Oxygen (TPO) number is even more important than the strict DO measurement IMHO. DO will react over prolonged periods, as stated, and if you test immediately, it will show you if you have issues with a particular filler head. The TPO measurement will show you any issues that may develop over time. I would contend this is a more accurate and repeatable method for testing packaged oxygen problems over headspace testing. But unfortunately you just won't get accurate results after shipping, it has to be done almost immediately after packaging. That's why I was suggesting the travel.

                I have used the Orbisphere as well (in fact quoting one for another facility right now), and it is a good machine overall. I tend to prefer The Beverly from Hamilton for the cost (slightly less) and usability. The Anton Par is very nice, and can include dissolved co2 readings, however it is priced so high, I would rather buy another tank (or three) and a Zahm volume tester.

                Low tech, you can try force aging your bottles to do a sensory analysis on the oxygen situation, but that means you likely have bottles in the market already. Even if this is true, you can use your results over successive batches to try to isolate a particular filler head or procedure.

                Let us know if you get good information from testing at a lab. I'd like to hear your experience.

                Comment


                • #9
                  There is a simple protocol for checking potential oxygen issues at packaging and identifying the sources, as follows:

                  1. Take 4 bottles/cans direct from the filling operation (immediately after capping)
                  2. Analyse 2 immediately, unshaken for DO2
                  3. Whilst analysing those, shake the other two to equilibrate headspace & dissolved gases
                  4. Analyse the two shaken samples for DO2

                  The results will fall into one of four brackets:

                  A. Unshaken & shaken both low and similar = beer good, filling good
                  B. Unshaken low, shaken higher = beer good, filling needs attention
                  C. Unshaken & shaken both high & similar = beer needs attention, filling good
                  D. Unshaken high, shaken very high = beer needs attention, filling needs attention

                  An unshaken sample analysed promptly will give good correlation to the O2 state immediately before it the filler head, since it takes a while for any headspace gases to equilibrate with dissolved (hence shaking two samples for the shaken test). This should also correlate well with the DO2 as measured in the tank feeding to the filler.

                  This process can be carried out on individual heads, if there is reason to suspect head-to-head variance.

                  It is possible for shaken samples to be lower than unshaken. This occurs when the headspace has virtually no O2 present and the dissolved level in the beer is higher. The O2 equilibration is then driven, during the shake, from dissolved to gaseous phase.

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