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Why is my kettle looking worse after CIP?

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  • Why is my kettle looking worse after CIP?

    We clean our kettle after every brew with 2% caustic (Orica C4) at between 65C-80C for at least 40 minutes of recirculating through the spray-ball. Before we start the stainless is pretty decent looking - a few discoloured bits and some hop crud, but after CIP and rising the walls take on a brownish tinge and with the exception of some bright patches where the fixed spray-ball has hammered the walls it's far less shiny than before cleaning.

    To remove this brownish deposit requires much hard labor with a #0000 3M scrubbing pad (non-scratching).

    Re-causting the kettle softens this deposit and it can be removed with ease using the same #0000 scrubbing pad.

    Nitrobrite (Orica nitric/phosphoric blend), does not remove this.

    Is it our water? Protiens on the walls that are darkening from the heat of cleaning that were there all along? Something else? It's taking far longer and more cleaning chemicals that I think it should take to get our kettle and MLT as clean as I'd like between brews.
    Regards,
    Chris Mills

    Kereru Brewing Company
    http://kererubrewing.co.nz

  • #2
    you have baked on the proteins.

    Loosen them first with a 1.5% phos or nitric. Ensure all surfaces getting wetted during 20-30 min acid circ. If you can pump this soultion into the mash tun after, great! close all mash tun outlets, pump it over and let it soak everything (submerge the screens).

    W?hat I find is that instead of actually rinsing kettle walls, if you have a grant tank or something you can pull from, "rinse" the tank with 1% , but make sure this soultion goes to drain. I only use maybe 30 gallons of this solution. Then I make up a 2% caustic and circ this for 20 minutes at room temps. Then turn the jacket on and heat caustic up to ~ 150F and circ for 10 minutes. Often times at this stage I will add Lerasept -O, an alkaline booster. Circ this for another 10 minutes. Then drain the mash tun of the acid, rinse mash tun with hot water, and then use this lerasept-o/cuasitc mix on the mash tun. Once kettle is empty, rinse with hot water while mash tun is under CIP. Then completely rinse with hot water.

    I have tried bru-r-ez. I have tried PBW. I have tried other chemical suppliers. However this method I just described gets the kettle clean enough where I don't have to climb in and manually scrub!!!

    Cheers
    Derek N. Luke
    Brewmaster
    Newport Storm Beers

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    • #3
      Interesting. I had always thought that acid wash should come after alkaline, but that sounds rather encouraging!
      Regards,
      Chris Mills

      Kereru Brewing Company
      http://kererubrewing.co.nz

      Comment


      • #4
        15 years brewing. Acid before caustic in the kettle. and I used to get inside and scrub manually...

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        • #5
          I agree with Derek on trying acid before caustic.

          A few other thoughts: 80C seems pretty hot for caustic. You may want to keep your cycles down near the 65C end of your range to prevent burning on the proteins. I am not familiar with the brand Orica, is that the temperature range they suggest? Do you have better/different results on one end of the temp range or the other?

          Talk to your chemical supplier about the possibility of using an oxidizer additive. I know RMC and Loeffler carry such additives in the US. A little goes a long way to improve the performance of caustic in cleaning the burned on stuff.

          As far as using acid before caustic, I have **anecdotally** heard that acid before caustic works best if you have soft water. My personal experience testifies to that (at four different places, three with soft water, one with harder water.)

          My current regimen is: Caustic (150F [65C]) with oxidizer additive in the kettle and backwards through the HX daily after brews. Acid cycle before the caustic at the end of the brewing week. I sometimes have a slight protein blush mid-week, particularly at ground zero for the firebox (direct fired kettle) and on a few of the welds on the lower walls but all in all I'm VERY happy with my results. I have never had to go into the kettle.

          Cheers- Mike

          Comment


          • #6
            Originally posted by dereknobleluke View Post
            15 years brewing. Acid before caustic in the kettle. and I used to get inside and scrub manually...

            For a fermentor/soiled brewhouse, I have to agree.

            Acid first. Even weak acid (like 1/3 the strength you would use for an acid wash), circulated cold to warm for 20 min before the caustic wash will likely help.

            It loosens all the crap, and sets up your crusty fermentor/kettle/brewhouse for your caustic wash (which will be as hot as you can make it).

            Seems counter-intuitive, I know, but it works,

            I find it also helps with saponification of the protein deposits (foaming) in the caustic cycle as well.

            Too much foaming will seriously impede impingement through your spray ball/jets resulting in a less than satisfactory washing cycle.

            Good luck.

            Liam
            Liam McKenna
            www.yellowbellybrewery.com

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            • #7
              I thought caustic made calcium precipitate out of solution leaving behind that whitish oxalate scale. After a caustic cycle on our kettle, we get a good amount of stubborn oxalate scale. Acid washing after removes this.

              Are you guys getting any scale by running acid first followed by caustic?

              Comment


              • #8
                Pre-caustic rinse

                Originally posted by dereknobleluke View Post

                ... if you have a grant tank or something you can pull from, "rinse" the tank with 1% , but make sure this soultion goes to drain. I only use maybe 30 gallons of this solution...
                This is a great tip. The first rinse is aided by a bit of caustic, which helps with cleaning, but also ensures that there is no residual acid to lower the pH/effectiveness of your recirculating caustic wash.

                In facilities w/ CIP skids, I'll often include a recovery tank that is used to hold the first rinse after the caustic wash. We then use the contents of this tank for the rinse before the caustic wash. Its a good practice when your water, chem, or waste treatment costs are high, plus it is environmentally friendly. You can do the same with a cheap poly tank.
                Kyle Kohlmorgen
                Process/Automation Consultant
                St. Louis, MO

                Comment


                • #9
                  Sodium Precarbonate

                  Not sure if you resolved your issue or not. I know a lot of people will run an Acid cycle prior or post caustic. This obviously works, the only downside is the additional step that is required (more time). I had the same problem as you, thought that I was not running the dilution correctly. Watched the CIP video on the ASBC website and realized that caustic alone will not do all the work. The solution is to add hydrogen peroxide (sodium precarbonate NA2CO3) in with your caustic cycle. It works wonders and you can eliminate the additional acid step. I would still recommend running acid once a week or at least twice a month anyway. Also, cycling PAA through your kettle + HX post caustic rinse will also help. It also allows you to keep your HX packed with sanitizer Cheers.

                  Comment


                  • #10
                    You can use acid first but you should always use acid after caustic due too. You need to use acid to counter caustic to protect the stainless.
                    Aron Levin
                    St. Florian's Brewery
                    Windsor CA 95492
                    www.stfloriansbrewery.com
                    www.facebook.com/stfloriansbrewery

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