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Anaerobic/Aerobic Bacteria - Acceptable Levels in Brewing Water

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  • Anaerobic/Aerobic Bacteria - Acceptable Levels in Brewing Water

    We've recently had some issues with sulfur in our beer. We use an R/O filter with particle filters and also charcoal filters. We had the water tested and there were high levels of anaerobic & aerobic bacteria in our R/O tank. We recently upgraded the size of the charcoal filter and added a UV light right before the membrane. I want to implement a regular water testing program and would like to know what the acceptable levels of anaerobic and aerobic bacteria is in brewing process water. Trying to catch the problem before it's in the beer! If you also have any recommendations on how to conduct these tests that would be helpful too.

  • #2
    Bacteria in hot-side water is not necessarily detrimental to brewing. But the fact that your RO water is presenting and supporting bacteria, is troubling. That suggests that your water source contains dissolved organic carbon and possibly nitrogenous compounds. Considering that your water is generally out of the Everglades, the possibility of those compounds in the water supply is possible.

    Having worked on the Ft Lauderdale water supply, I know that its lime-softened groundwater and it should be fairly well suited for brewing. Why have you implemented RO treatment for your brewing water? The one thing that concerns me with Ft Lauderdale water is the potential for geosmin and methylisoborneal in the water (mucky taste). Those compounds can be largely corrected with properly sized activated carbon treatment.

    To help resolve the bacteria problems, I suggest that flushing the membranes and other contacting piping be flushed with a metabisulfite solution to help kill existing bacteria. However, if the dissolved carbon and nitrogen content of the raw water is significant, the problem will be back eventually.
    WaterEng
    Engineering Consultant

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    • #3
      Agreed. How are you removing the disinfectant from your RO feedwater?

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

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      • #4
        ZERO.
        Put a UV light in a re-circulation loop off your RO water storage tank. And keep that tank blow 40f or above 160f, if you can.
        Brewmaster, Minocqua Brewing Company
        tbriggs@minocquabrewingcompany.com
        "Your results may vary"

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        • #5
          Originally posted by LauderAle View Post
          We've recently had some issues with sulfur in our beer. We use an R/O filter with particle filters and also charcoal filters. We had the water tested and there were high levels of anaerobic & aerobic bacteria in our R/O tank. We recently upgraded the size of the charcoal filter and added a UV light right before the membrane. I want to implement a regular water testing program and would like to know what the acceptable levels of anaerobic and aerobic bacteria is in brewing process water. Trying to catch the problem before it's in the beer! If you also have any recommendations on how to conduct these tests that would be helpful too.
          Is this an atmospheric (un-pressurized) tank? If so, a UV recirc loop would be customary.

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

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          • #6
            WaterEng, we use RO because our water comes from two different water treatment plants and the water makeup is inconsistent. We recently realized that our carbon tank was improperly over sized sized so we just installed a new one. We also have done lots of water quality testing and the city water has 156 MPN/ml of HPC. We installed a UV light prior to the carbon filter as that was the area we were seeing the most bacterial growth. I'm hoping with the UV and properly sized carbon filter with correct flow rates we will be in a much better state, we just performed water analysis of our filtration equipment last week and will repeat in a couple weeks. We believe that the large amounts of dead bacteria (cultivated in carbon tank, killed in HLT) was causing the sulfur during fermentation. We also perform weekly chlorination of filtration equipment (excluding the membrane). But we're hoping to get away from or reduce cleanings if the new equipment works properly.

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            • #7
              Sure that your sulfur problem is with raw water? I've seen sulfur come up many times, but most often due to fermentation issues, high levels of sulfur salts, failure to drop bottoms, and other issues downstream of the raw water. Although I agree with the above--that you need to get bacterial to ZERO--if a warm glass of water doesn't reek of sulfur, perhaps there are other issues beyond a faulty water conditioning program. Also agree that RO is a last resort and overly complicates your water treatment system by raising your equipment purchase cost, running cost, maintenance cost, water cost, effluent cost, and is generally inferior water to brew with. How much different could the two municipal sources be? Best of luck!
              Phillip Kelm--Palau Brewing Company Manager--

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              • #8
                Honestly we're not 100% sure it's raw water but based on the water reports we've received we thought that's the most obvious place to start. We've performed sniff tests of our raw water after different stages of the filtration we get sulfur like odors at different levels, different times, different places...We use RO because we receive water from two different plants, either the amount of water we get from each plant varies or the water chemistry of the plants themselves vary so the mineral makeup is inconsistent. We felt that in order to make consistent beer we need consistent water, and it would be too difficult and costly to test the city water so frequently when it could really change daily...so RO seemed like the best solution.

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