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  • Fermentation tank cleaning

    I recently started brewing at a brewery where the cleaning regimen lapsed a bit, and now I have some 10 BBL unitanks with crud buildup under the manway door (i can feel it is rough, but cant see it). So my question is, what is the best way way to clean these tanks? I currently have chlorinated caustic and a chlorine-acid based sanitizer in the brewery.

  • #2
    chlorine based cleaners

    First thing I'd do is get rid of the chlorine based anything. Chlorine has the potential to be highly destructive to stainless steel. A little elbow grease should take care of the dried crud. Use a mild detergent and a scrub pad. You may have to scrub a little and let the crud soften a little and scrub some more until it's gone. Manway shadows are nigh on impossible to clean by CIP because they don't get coverage by either the sprayball or the flow of cleaners down the sidewalls. They should be cleaned by hand before AND after CIP. Bits of the the fermentation ring will wash down into the shadow during CIP and, if you don't rinse it off by hand, it tends to stay there and dry into exactly the kind of crud you're dealing with now. If it's not possible to get a step ladder and poke your head inside to confirm that it's clean, use a mirror or even a digital camera to get a view under the manway before you sanitize the tank (with a non chlorinated sanitizer). Also look at any other potential shadows that can harbor soils such as tank sidewall penetrations for sample valves, especially if any of those penetrations have a depth greater than 3x the diameter of the penetration. i.e. if you have a 1.5" port that extends more than 4.5" from the wall of the tank, it is unlikely to be reliably cleaned by CIP and will require some form of manual cleaning.
    Steve Bradt
    Regional Sales Manager
    Micro-Matic Packaging Division
    Eastern United States and Canada
    sbradt@micro-matic.com
    785-766-1921

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    • #3
      Oxalates and Chlorine

      All right, there are two things here that I'd like to comment on...

      First of all, if I had to guess, you've probably taken the chlorinated caustic mix and a scour pad to this crud. If you haven't, you should. I think that it's probably not going to come off this way, but that's a good diagnostic tool. When that doesn't work, you'll need to rinse the tank and hit it with some mineral acids (my personal favorites are phosphoric and nitric in a Five Star blend). The crap in the shadow is probably calcium oxalate (beer stone), and won't come off in anything but a potent solution of strong mineral acids. And, if you can see it, an acid cycle in the tank will be insufficient for the task as well. I think that you're stuck scrubbing the crap out of there.

      Second thing, I wouldn't worry about the chlorinated caustic. From what little I understand, chlorine will not interact with stainless in a basic environment. I've know people (myself included) to dump bleach in with the caustic wash to remove some of the more obstinate gunk that builds up from time to time. When you get into acidic solutions, it would probably be best to avoid chlorine: that being said, Cl02 is used as a sanitizer in beer, wine, and milk applications, and doesn't seem to have any ill effects on the stainless. I'm not sure why, but you're chemical suppliers would have the answers.

      And to reinforce what was already said, shadows are a bitch. Stay on them.

      Good luck,
      Bill

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      • #4
        Originally posted by william.heinric
        All right, there are two things here that I'd like to comment on...

        First of all, if I had to guess, you've probably taken the chlorinated caustic mix and a scour pad to this crud. If you haven't, you should. I think that it's probably not going to come off this way, but that's a good diagnostic tool. When that doesn't work, you'll need to rinse the tank and hit it with some mineral acids (my personal favorites are phosphoric and nitric in a Five Star blend). The crap in the shadow is probably calcium oxalate (beer stone), and won't come off in anything but a potent solution of strong mineral acids. And, if you can see it, an acid cycle in the tank will be insufficient for the task as well. I think that you're stuck scrubbing the crap out of there.

        Second thing, I wouldn't worry about the chlorinated caustic. From what little I understand, chlorine will not interact with stainless in a basic environment. I've know people (myself included) to dump bleach in with the caustic wash to remove some of the more obstinate gunk that builds up from time to time. When you get into acidic solutions, it would probably be best to avoid chlorine: that being said, Cl02 is used as a sanitizer in beer, wine, and milk applications, and doesn't seem to have any ill effects on the stainless. I'm not sure why, but you're chemical suppliers would have the answers.

        And to reinforce what was already said, shadows are a bitch. Stay on them.

        Good luck,
        Bill

        Yep, agree with Bill completley......its beerstone and you'll need to scrub with a fairly concentrated phos /nitr blend...should'nt take too long though, we had the same issue with sone used tanks we picked up a few years ago.

        JackK

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        • #5
          Yes, definitely beer stone.

          Cacium phostphate is insoluble - so go for a nitric only acid, or insoluble calcium phosphate will simply replace insoluble calcium carbonate adn oxalate.

          Or better, get a very high EDTA type detergent

          If you have high mineral solids in your water, then you may also need to check the formulation of the detergent with your supplier, to make sure it is OK for the water. And you may want to acid dose the final rinse to get rid of scale build up - BUT - if using chlorinated caustic, only dose the acid AFTER all caustic has been removed - or you will soon have a sieve for an FV

          Cheers
          dick

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          • #6
            Put on gloves and goggles and spray the area with undiluted acid, let soak overnight and it will come right off with some scrubbing. Most chem. companies will sell a 'foamer' product to add to acid/caustic for applications such as this.
            the inside of HLT's are big for calcium buildup too, one of my winter projects...
            Brewmaster, Minocqua Brewing Company
            tbriggs@minocquabrewingcompany.com
            "Your results may vary"

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            • #7
              Thanks for that info Brian. It is great when the detail is provided by a topic expert. Esp regarding chlorine and safe Ph levels.
              Tim Eichinger
              Visit our website blackhuskybrewing.com

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