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Thread: Prevent Bacteria Growth in HLT after carbon filter

  1. #1
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    Question Prevent Bacteria Growth in HLT after carbon filter

    Hi
    We are opening a brewery and we will have a 20 BBL HLT. We would like to use carbon filter to remove Chlorine / Chloramine and bad taste.
    We realize it may facilitate bacteria growth in the HLT since the water lose its bacterial protection.
    Is there some kind of HLT cleaning procedure to follow to minimize that bacteria growth or is it understood that the water from the HLT will be boiled and it shouldn't be a source of contamination within the brewhouse?
    Thanks and sorry if this question is trivial
    Matt

  2. #2
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    We keep our HLT at 190 F and have never had an issue with bacterial growth.

  3. #3
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    80 C is normally OK, but I suggest you include the facility to clean it periodically - especially if your water has any amount of carbonate / bicarbonate in it. But then you should be treating the water for this in the chilled liquor tank so you don't foul up the wort chiller.
    dick

  4. #4
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    Question

    Quote Originally Posted by dick murton View Post
    80 C is normally OK, but I suggest you include the facility to clean it periodically - especially if your water has any amount of carbonate / bicarbonate in it. But then you should be treating the water for this in the chilled liquor tank so you don't foul up the wort chiller.
    We have ~250 ppm of HCO3. Water-wise we were planning on having:
    - Carbon filtered to HLT only
    - Water softner to steam generator and for tank / vessels cleaning
    - city water (as is) for the rest of the building

    No CLT in our setup since the city water is fairly cold and we plan on brewing ales.

    Regarding the carbon filter, with a 2" pipe, do you recommend a min / max flow rate? We will do double batch brews on brew day.

    Thanks

    Matt

  5. #5
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    Quote Originally Posted by Mattieu View Post

    Regarding the carbon filter, with a 2" pipe, do you recommend a min / max flow rate? We will do double batch brews on brew day.
    Carbon filters have a design flow rate, and you should probably not exceed 50% of that. The actual rating depends on the filter and the media type (e.g. carbon block as opposed to granular activated carbon, etc).

    I'm guessing here, but I'd say the max flow is probably a lot lower than you're expecting.

    Regards,
    Mike Sharp

  6. #6
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    3 parts
    Firstly, the carbon filter flow rate. Simply work out how much water you need to treat to be able to refill the water tanks between first and second brew, how long you have got to refill, making sure you don't refill so far you can't maintain your target temperatures accurately - and you have you minimum flow rate. Make sure you have a bit of excess capacity to allow for any slowing down as the filter gets used and might block with other particulates.

    Secondly, with that level of bicarbonate, it must be treated to remove the bicarbonate before heating up, by any method. If you are only brewing ales, you may get away with sulphuric acid treatment only, but are likely to find the amount of residual calcium sulphate is excessive for the flavours of at least some of the beers you will brew. So you may want to consider lactic or phosphoric acid, or a mixture of two of the three. At this level of bicarbonate, you should have a degassing facility - even a simple large holding tank will be better than nothing. Whatever you do, do not pass untreated water through your wort chiller as calcium carbonate will be precipitated on the water side of the plates, fouling, restricting heat transfer, and at extremes even flow rate. CO2 gas will also be evolves in the water whilst in the chiller, which will come out of solution.

    If you simply run untreated water into the hot water tank and heat up, then you will foul up the heating surfaces and the tank will require regular and probably frequent acid descaling for it to remain efficient.

    If you don't treat the water to remove the carbonate and or remaining bicarbonate, the water will adversely affect the mash pH, and so affect mash conversion, extract, etc, so you will not produce beer to the flavour and colour profile you want.

    Thirdly, I strongly advise a chilled liquor tank simply for good control of the wort temperature and the recovered hot water temperature - so you don't produce excessive amounts of warm, but not suitably hot water, and waste half of it, or produce excessively hot water and then have to top it up, mix it etc.
    dick

  7. #7
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    To back up some of Dick's comments:

    We have a carbonate hardness of 130-160 ppm. We don't treat our water. It's a complete PITA to keep the HLT and heaters going. We use 3 Rinnai C199 tankless heaters to heat our hlt and make-up water. I clean the filters on them daily, and have to acid-wash the heaters every two weeks. We acid wash the water side of our brewhouse HX every month.

    With the carbonate levels you have, good luck. You'll be cleaning your hot liquor system constantly. You'll be replacing valves in the HL system constantly--high carbonate eats ball valves very quickly, both from abrasion due to scale and from the CO2 released when the scale forms. You'll be amazed how many problems the hardness will cause you, and carbonate hardness is of little or no use in brewing.

    As for bacterial growth in the HLT, we keep ours at 185F and have never seen any evidence of anything growing in the HLT--and I climb inside of it to clean scale out every three months.

    Make sure your HLT has a manway--You'll be using it frequently.
    Last edited by TGTimm; 12-04-2018 at 11:58 AM.
    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

  8. #8
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    Question

    Quote Originally Posted by dick murton View Post
    3 parts
    Firstly, the carbon filter flow rate. Simply work out how much water you need to treat to be able to refill the water tanks between first and second brew, how long you have got to refill, making sure you don't refill so far you can't maintain your target temperatures accurately - and you have you minimum flow rate. Make sure you have a bit of excess capacity to allow for any slowing down as the filter gets used and might block with other particulates.

    Secondly, with that level of bicarbonate, it must be treated to remove the bicarbonate before heating up, by any method. If you are only brewing ales, you may get away with sulphuric acid treatment only, but are likely to find the amount of residual calcium sulphate is excessive for the flavours of at least some of the beers you will brew. So you may want to consider lactic or phosphoric acid, or a mixture of two of the three. At this level of bicarbonate, you should have a degassing facility - even a simple large holding tank will be better than nothing. Whatever you do, do not pass untreated water through your wort chiller as calcium carbonate will be precipitated on the water side of the plates, fouling, restricting heat transfer, and at extremes even flow rate. CO2 gas will also be evolves in the water whilst in the chiller, which will come out of solution.

    If you simply run untreated water into the hot water tank and heat up, then you will foul up the heating surfaces and the tank will require regular and probably frequent acid descaling for it to remain efficient.

    If you don't treat the water to remove the carbonate and or remaining bicarbonate, the water will adversely affect the mash pH, and so affect mash conversion, extract, etc, so you will not produce beer to the flavour and colour profile you want.

    Thirdly, I strongly advise a chilled liquor tank simply for good control of the wort temperature and the recovered hot water temperature - so you don't produce excessive amounts of warm, but not suitably hot water, and waste half of it, or produce excessively hot water and then have to top it up, mix it etc.
    Dear Dick

    Thanks for taking some time to answer and help I am very thankful.

    #1: Carbon Filter - Understood. I will work with some local suppliers and their technicians / engineers to define that. Thanks again

    #2: Water filtration - Your recommendation is wise and we will follow it. I am not familiar with many things which you are referring to and I apologize. I will document myself over the next couple of days but if you have pointers, I would love to get them.
    #2.1: sulphuric acid treatment - can you expend on that? Is it a "manual" treatment done in the HLT directly or is in an inline treatment done as water flows?
    #2.2: Currently, we our R&D equipment (home brew style) we modify the water profile using Brun Water and we primarely add gypsum; calcium chloride & lactic acid. The addition is done manually in the kettle as we warm up water for the Mash Tun and HLT. We also use a RV carbon filter. Is your recommendation to have lactic or phosphoric acid addition be similar in process? Add it to the HLT after fill up and before warm up?
    #2.3: degassing facility - what do you mean? Is it a holding tank before HLT? Would it need to be the same size as the HLT?
    #2.4: wort chiller - understood; it is clear that we won't use city water "as is" in the wort chiller
    #2.5: risk of untreated water in HLT - clear and understood
    #2.6: water treatment solutions. You referred to sulfuric acid / lactic and / or phospric acid treatment. Thanks. Local people are trying to sell me on the salt softener but I am fearful of that mainly because of the sodium addition (we already have 80 ppm) and cost (salt & ownership). We are also looking at this technology: https://www.ecobulles.com/en/home/ It is adding CO2 in the water to lower pH. It is designed and manufactured in France (where our brewery is / will be). Are you familiar with this technology? Is there an equivalent in the US and is there some feedback on the benefits / features? Would it solve my problem or help us?

    #3: CLT - Ok, let me see if we can add it to our design. We are close to signing the agreement and we are already over budget.

    Here is a snapshot of the water profile given by the city for our part of town - it may help in the discussions:
    Ca 22
    Mg 10
    Na 88
    SO4 28
    Cl 52
    HCO3 248

    pH is 7.2

    Thanks again

    Matt

  9. #9
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    Forget CO2 injection to solve your hard water problems. CO2 comes out of solution when the water is heated--which is exactly what's happening when you carbonates turn to scale--or the pressure is dropped. You'll be spending money on CO2 and not solving your problem.

    Look into nanofiltration. This is similar to RO, but reduces the hardness without removing all ions.

    Water softening is a field full of venomous snakes and snake-oil dealers.
    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

  10. #10
    Join Date
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    As Timm says - CO2 addition will not work on water. I do know breweries that use it for neutralising, or at least, helping to neutralise high pH effluent, high from CIP caustic based detergents - but that is obviously a whole different subject. H2CO3 will adversely affect the mash pH - you cannot use it for brewing, even if it works on domestic water systems / drinking water.

    H2SO4 addition - if my maths is correct, and I am more than happy for someone to correct me, if you added sulphuric acid only to neutralise the bicarbonate you would end up with about 200 ppm sulphate in your water (180 new + existing 24). This would probably be too high for your beers, unless you want what is known in the UK as the "Burton snatch" - a noticeable H2S aroma.

    The problem with acid treating with any of the acids is that the bicarbonate breaks down to water and CO2, which when the water is heated will be given off as gas bubbles, which can make handling difficult, damage pump impellers and if extreme enough, can damage chiller plates and seals due to the volume taken up by the gas bubbles. So you need to allow time for it to degas naturally, or better, rouse it to cause CO2 gas bubbles to form and be vented off. In a large brewery they use degassing towers of packed columns with a forced updraft of air to strip out the gas. In your case, treating it before overnight storage and chilling, with a recirculation system run periodically to ensure consistent temperature will almost certainly do the trick. This can be simple manual addition to the tank once you have refilled it, or use a carefully calibrated / controlled dosing pump to dose acid as you fill the tank. There has been a fairly recent discussion on this, so do a search and you will find some ideas.

    You need to treat the cold water before it is used to cool the wort, and reclaimed as hot water for the next brew / cleaning etc.
    dick

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