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High pH in HLT/CLT

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  • High pH in HLT/CLT

    Hi there - we're a bit perplexed by a pH issue with our brewing water. Long story short, recently opened so brand new system and piping all around. We are routinely getting pH readings in the high 8s and low 9s in our HLT and CLT. We have taken samples all around the brewery and tap room at different points. The water coming out of faucets and sinks is closer to normal for this city (mid 7s).

    At first we suspected something in the HLT/CLT so we re-CIP'd both tanks with caustic and acid and hit the inline heat exchangers as well. No movement.

    This morning I pulled the water feed pipe to the HLT and CLT and once again showed readings in the low 9s. So the issue probably isn't the tanks - its the supply water to both the HLT/CLT. However the piping in the building is all coming from the same source as the water coming in mid 7s to the taproom/sinks/other outlets.

    Seems like the problem is in the plumbing for the brewhouse - anyone else noticed something similar? Is there something in piping that could be raising the alkalinity of the water?

  • #2
    Is your brewing water softened? Madison-area water, which is extremely alkaline, is usually in the mid-7s but can increase into the 9s when softened. If somebody (often not the brewer in these instances) included a fancy water softening system in the build-out, you may be able to flip a few valves to bypass it.



    • #3

      Originally posted by jwalts View Post
      Is your brewing water softened? Madison-area water, which is extremely alkaline, is usually in the mid-7s but can increase into the 9s when softened. If somebody (often not the brewer in these instances) included a fancy water softening system in the build-out, you may be able to flip a few valves to bypass it.

      This is a very interesting subject. While the Alkilinity of Salt Softened water is usually notably higher, I have never encountered a PH change as is being described.
      I would like to hear the water chemistry experts chime in on this one.
      Also total alkilinity and PH are not the same thing.
      There are a major lot of contradictory publications on dealing with salt softened water that defy fully what field experience has shown to be the case. Its a labyrinthe, and as thus full of experts that cannot agree on many points and must be taken on a case by case basis with heavy coordinated analyses carried out. When you are salt softening VERY hard water such as back in Texas, you naturally end up with a high amount of sodium bicarbonate in the finished water. This is what gives salt softened water the characteristic slick feel.

      Last edited by Starcat; 10-13-2019, 10:25 AM.
      Warren Turner
      Industrial Engineering Technician
      HVACR-Electrical Systems Specialist
      Moab Brewery
      The Thought Police are Attempting to Suppress Free Speech and Sugar coat everything. This is both Cowardice and Treason given to their own kind.


      • #4
        Going off the water softener topic. Any chance the lines running to the brewhouse are not softened water but the rest of your facility is?


        • #5
          Do you have a new carbon filter? If so, how extensively have you backflushed it?

          Also, try blending barley with water in a small proportion similar to what your normal water:grist ratio is and test pH there.
          Last edited by Jeremy N King; 09-17-2019, 11:50 AM.
          Jeremy King, Brewery Design Consultant, Experienced Commercial Brewer
          Craft Kettle Brewing Equipment
          New Orleans, LA

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          • #6
            High calcium carbonate content dissolved in the water, which is then reacting with CO2 to create bicarbonate and thus increase the pH ????? Think I'm clutching at straws here, but it is the only thing I can think of.

            What is your water analysis??


            • #7
              Following up on this topic, which I started way back when we opened in September. Seems like 6 years ago but it's only been 6 months. I'm sure you can relate.

              Anyway, we are STILL experiencing high pH levels in our HLT (which is what we are using for our brewing water, hence the main issue here). So far we've been utilizing small amounts of Wyermann sour malt to get our mash pH levels in line but sparging with high pH water sucks, and generally we'd just like to solve this problem anyway.

              The HLT system is a standard non jacketed stainless tank. Created by Sprinkman. It utilizes a stainless-piped recirculation pathway that routes through a steam fed HX (steam on one side of the plates/HLT water passes through the other side). Everything should be up to spec and it (by all accounts) is well made and still brand new.

              The water goes into the HLT at a standard city water pH in the 7.5-7.8 range usually. If we let the water just sit in the HLT without recirculating it stays about the same. We've seen a slight amount of upward creep but maybe 0.10-0.20 at most.

              If we turn on the steam and run the recirculation to heat the water, we see a gradual rise in pH over a span of about 2-24 hours to levels as high as the low 9s. Wowza.

              -Based on feedback in this thread we've back flushed our carbon filter just to be safe. That said the water comes in at 7.5 so not sure how this would affect the situation anyway.
              -We do not use water softening measures on the water that enters the HLT. We do use a softener on the water supply to our boiler
              -We have had Ecolabs perform several analysis runs on our water. Nothing out of the ordinary.
              -I had Alfa Laval stop in and inspect the HX plates to see if we were experiencing steam creep into our HLT water. They ran a dye test and we even replaced all the plates and gaskets. Nothing changed.

              At this point we are kind of at a loss. The water is picking up OH- ions or something along the way during recirculation/heat up and we have no idea where. Figured I would ask this thread one more time in case someone has an idea.

              Thanks again!


              • #8
                My previous suggestion - I think I got it the wrong way round. Calcium bicarbonate has a lower pH than calcium carbonate. On heating, the calcium bicarbonate decomposes to calcium carbonate and CO2 - so the pH rises.

                So the way I would treat it would be to add some acid - food grade sulphuric if it isn't going to screw up the rest of your mineral composition, otherwise possibly phosphoric or lactic. I would expect you to be building up hard water scale on the water side of the heat exchanger plates as well. So you will eventually get poor heat transfer. So you will probably have to acid wash the water side of the PHE periodically.

                The carbon filter is for chlorine / chloramine removal mainly, not hard water ion removal.


                • #9
                  Dick, you beat me to this exact response! The only thing I would add is that if the carbonate alkalinity is high enough to cause this issue, using phosphoric acid would probably result in deposits of calcium/phosphate solids such as apatite instead of calcium carbonate. I've had good results with lactic acid.



                  • #10
                    Is your carbon filter using acid-washed media as it should be? Standard carbon media can have a high pH following manufacture and it can impart an elevated pH to the water passing through it. The acid-washing helps neutralize that problem. It sounds like you may need to perform an acid rinse on the carbon unit to help neutralize the media.

                    Regarding apatite formation, the calcium concentration in the water will need to be fairly high for a phosphoric acid addition to create that precipitate. The concerns about loss of calcium from phosphoric acid addition are overblown.
                    Engineering Consultant


                    • #11

                      Going on a tangent and assuming that carbonate alkalinity is causing the pH increase - i.e. not to say that the carbon filter media isn't the problem - wouldn't that imply that a lot of calcium is likely present? If the carbonates were to originate primarily from magnesite or even dolomite, I'd be curious how the precipitation of magnesium phosphates would compare with calcium phosphates. Anyway, precipitation of calcium phosphates with phosphoric-treated water is certainly a problem with the groundwater in south-central Wisconsin (total alkalinity of ~300 mg/L as CaCO3) - and I've experienced it personally. Not that I've quantified the loss of calcium, but dealing with any chalk-like deposit on brewing equipment is a pain.

                      That said, I'd expect Milwaukee water to come from Lake Michigan and contain a lot less calcium carbonate. So I'd agree that my concern about phosphoric acid could be overblown for hophead34, but it's hard to say for sure without seeing a water report. That's why I included the "if the carbonate alkalinity is high enough" qualifier. With that in mind, I'd be interested to know how much calcium carbonate would be needed to raise the water's pH from the mid 7s to 9ish during heating. Is that something you've looked into?



                      • #12
                        A bit slow to respond, but the simple answer is no. I've not seen anything published, though admit to not having searched, and have never looked into it on my own behalf - I wouldn't have made a mess of the earlier responses if I had (I hope!!).

                        I would be interested if anyone does have any sort of information which differs from this source which gives the pH of CaCO3 solution as 9.91 at concentrations of 1 mM 10 mM 100 mM per litre (valid for standard conditions at 25°C, 1 atm)


                        • #13

                          While Milwaukee is on Lake M, it depends where in the city a user is, if their water is from the lake. The Great Lakes Compact now requires that Great Lakes water stay within the Great Lakes basin and Milwaukee and hundreds of other municipalities have had to replumb their utilities and water supplies to meet that requirement. Suburbs away from the lake could now have really crappy groundwater supplies that are hard and alkaline. Your experience with chalky precipitation and sedimentation is not a surprise.

                          I haven't explored the saturation limit of magnesium phosphates, but I'm guessing that it is much higher than that for calcium phosphates and isn't a problem.
                          Engineering Consultant


                          • #14
                            Has anyone come across an inline dosing system to reduce water pH into the water filter or HLT. Our water pH is 7.8-8.2 depending on the time of year. We have been dosing the HLT with phosphoric and it has reduced astringency. We would like to find a way to automate this process


                            • #15
                              Have you considered a small dosing pump?
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