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Campden/Potassium Metabisulfite for chloramine removal

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  • Campden/Potassium Metabisulfite for chloramine removal

    I recently landed a very small part-time job as an assistant brewer at a small brewpub with a 3.5 barrel brewery. After assisting with one full brewday I was surprised to find that they are not filtering or treating their city tap water for chlorine and chloramines which I know are present in the water supply. On the homebrew level I have always used campden tablets to deal with chloramines. I realize that a carbon block filter would be the ideal solution, but one of those does not appear to be on the horizon in the near future.

    In the 3.5 barrel-ish brewpub world is anyone out there using campden tablets or Potassium Metabisulfite to treat their water for chloramines?
    Last edited by NectarOfTheGods; 02-24-2012, 08:19 AM.

  • #2
    Campden tablets/metabisulphite will remove chloramines and at home brew volumes this is the simplest method to use but if you are going to routinely need to remove chloramines on larger volumes of water I would recommend using a more robust method such as carbon filters. This will give you a water clean of chloroamine without adding something that could potentially give you flavour taint when used to dechloroamine a large volume of water.

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    • #3
      I've never used them commercially, but I'd consider adding 30 mg of sodium metabisulfite or 35 mg of potassium metabisulfite per gallon of water in your situation. It would be a lot easier than crushing up a bunch of tablets. Anyway, an A.J. deLange article on chlorine/chloramine (available at http://ajdel.wetnewf.org:81/) claims that those rates will treat the worst-case scenario of 3 mg/L chloramine. It'll also treat 6 mg/L of chlorine. If your water has 3 mg/L chloramine, the treatment will result in 3 mg/L of extra chloride ions and 8 mg/L of extra sulfate ions. If your water has 6 mg/L of chlorine, the treatment will result in 6 mg/L of extra chloride ions and 8 mg/L of extra sulfate ions. Those are pretty small changes. If your water has less chlorine or chloramine, the treatment will result in some sulfur dioxide. Some of it will be driven off in the boil, and some will react with mash compounds to form sulfate ions that will approach the 8 mg/L maximum. Based on my experience of treating water that other brewers don't treat at all, and have no problems doing so (which implies low amounts of chlorine and therefore overtreatment with campden tablets on my part), the additions don't appreciably impact flavor.

      AnalysisAnnie, why would larger volumes increase the flavor impact if the same dosage rates are employed?

      Joe
      Ale Asylum

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      • #4
        A high-flow 20" carbon filter (similar to those sold for large domestic use) will produce around 5gallon per minute, so your 3.5 barrels would take about 20mins to filter.

        That seems like a decent proposition and is likely to be a more repeatable process than trying to ensure complete, even dissolution of campden tablets or powdered reagents.

        It also eliminates concerns about potential flavor impacts as both AA and Joe have mentioned.

        By using a stainless housing the whole system could be CIP'd and, if required, steam sterilized to ensure good micro.

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        • #5
          The advantage of using carbon is that it will remove other undesirables present in your water such as organics and you can be fairly certain that all the water will have come into contact with the active media as fitting to a main all water will pass through the filter and there is no need for mixing.

          Metabisulphite addition will need care as there is a legal obligation to declare sulphite over a certain level (currently 10ppm) because it is an allergen due to its link with asthma so you would need to check the remaining sulphite levels in your beer. At present the wine industry is having to move away from sulphites for oxygen control due to the issue with labelling and legal levels in final product.

          As for aroma and flavour taint, the addition of sulphite leaves the pathway open to sulphur compound formation a number of which have ppb thresholds and are unwanted additions to the flavour of your beer.

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          • #6
            Thank you for the insightful responses. As I stated initially, unfortunately a carbon filter is not in the budget at this point. I was primarily interested to know whether or not chloramine removal using metabisulfite is possible and practical at 3.5 barrels. Based on the information from jwalts it sounds like it is.

            an A.J. deLange article on chlorine/chloramine (available at http://ajdel.wetnewf.org:81/) claims that those rates will treat the worst-case scenario of 3 mg/L chloramine.
            The DeLange article is very interesting, thank you. It is very helpful to know that the metabisulfite removes chloramines in 1 minute or less.

            Unfortunately using the existing brewing procedure at the brewpub only the strike water will be able to be treated as presently the sparge is conducted using hot tap water run through an instant water heater. There is no HLT. But, I guess every little bit helps and its a step in the right direction as far as reducing chloramine levels in the finished beer. The plan would be to fill the mash tun with the strike water, then treat it with 35mg/gallon of pota meta before doughing in.

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            • #7
              Originally posted by WaterEng
              A 20" filter with activated carbon cartridge will not provide effective chlorine or chloramine removal for long if its run at 5 gpm. The flow rate should be on the order of 2 to 2.5 gpm to provide appropriate residence time with the carbon and improve the life and utilization of the media.
              Thanks. I gave the figure of 5gpm to show the order of magnitude for flow rate, so as to give an estimate for the time necessary to filter the OP's 3.5 barrels. Running at these lower rates still gives a cycle time for that volume of 40-50mins, which seems reasonable.

              As AA says, in recent years the wine industry has started to move away from sulphite use due to allergen labelling concerns. Whilst the primary use is as an oxygen-scavenger, it is the presence that is the issue rather than the reason.

              Mixing of any additives needs to be effective to ensure they are doing their job, whereas all the water has to pass through a filter.

              How does the cost of a 20" filter housing stack up against a good in-tank mixer?

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              • #8
                Originally posted by KWLSD
                How does the cost of a 20" filter housing stack up against a good in-tank mixer?
                We already have a state of the art in-tank mixer like the one pictured here: http://i00.i.aliimg.com/photo/v0/207...rill_mixer.jpg

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                • #9
                  I have a question concerning this thread. The brewery I work in does not have carbon filtering, and the last brewer suggested using Potassium Metabisulfite treatment. In the reading I've done, using this treatment will break down chloramine to ammonium and chloride. I don't have a chemistry degree, does anyone have the equation to calculate how much chloride I would be releasing, or is the level low enough to be negligible for calculating chloride additions?

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                  • #10
                    The Bru'n Water website has a Water Knowledge page that happens to have that equation.
                    WaterEng
                    Engineering Consultant

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                    • #11
                      Just dont add too much otherwise you will kill your yeast before you start fermenting.

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                      • #12
                        Originally posted by TL Services View Post
                        A high-flow 20" carbon filter (similar to those sold for large domestic use) will produce around 5gallon per minute, so your 3.5 barrels would take about 20mins to filter.

                        That seems like a decent proposition and is likely to be a more repeatable process than trying to ensure complete, even dissolution of campden tablets or powdered reagents.

                        It also eliminates concerns about potential flavor impacts as both AA and Joe have mentioned.

                        By using a stainless housing the whole system could be CIP'd and, if required, steam sterilized to ensure good micro.
                        This surprises me, because in our 3bbl brewhouse we purchased the smaller 10" 3 stage filter and had both water push through it tested as well as regular tap and found the results where the fillters were essentually useless... More reading suggested that for the carbon to have enough time to do its thing I would have to slow flow to a trickle..
                        As a result, we fill out HLT days before Our next brew and let the chloramine evap out... we have yet to have anyone say they taste and hint of it in the beers we make. We also add minerals and salts as needed depending on the beer based of our wards report.
                        Last edited by augiedoggy; 03-08-2020, 08:05 AM.

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                        • #13
                          When dealing with chloramines, carbon treatment is going to require much larger carbon vessels than many people (and system vendors) might suspect. Proper understanding of the chemistry and design of carbon units is essential when dealing with chloramines removal. Find a consultant with experience on the subject.
                          WaterEng
                          Engineering Consultant

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                          • #14
                            You'll not get 5 gpm treatment of chloramine from a 20" x 2.5" carbon filter.... even with a carbon block specifically designed to treat chloramine.

                            See rates you can expect here: https://www.buckeyehydro.com/chlorag...-carbon-block/

                            In nearly all cases, except for the smallest of breweries, a catalytic carbon tank is a more economical approach.

                            Russ
                            Probrewer.com Advertising Supporter

                            Buckeye Hydro
                            Water Treatment Systems & Supplies
                            www.BuckeyeHydro.com
                            Info@buckeyehydro.com
                            513-312-2343

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                            • #15
                              While its true that catalytic carbon can improve the effectiveness of activated carbon for chloramines removal, I've stopped recommending its use in commercial carbon units since it invites increasing the flow rate through the system and hydraulically-overloading the carbon bed. Hydraulic overloading is the reason that virtually all commercial carbon units have to have a backwashing capability. They are all improperly designed and employ an excessive hydraulic loading rate. Proper particulate filtration upstream of the carbon filter and proper hydraulic loading does make it possible (and preferrable) to run a carbon filter without ANY provisions or need for backwashing. Empty Bed Contact Time (EBCT) is not the only criterion for carbon unit design.
                              WaterEng
                              Engineering Consultant

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