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  • Thermal sanitation

    Hi all.

    I'm after some advice regarding hot water sanitation for hoses pre transferring wort/beer.

    My previous workplace ran >80c/176f water for 20 minutes. My current workplace runs 80c water for 5 minutes maximum.

    I haven't found any sources to confirm either method. I have seen a reference in a Bamforth text for 15-20 minutes at 70-80c, but it provided no rationale.

    I know you can calculate the pasteurisation units, but how many units are required?

  • #2
    Calculating PUs is meant to give you an estimate on the logarithmic kill rate of micro organisms. 1 PU is 60 seconds at 60*C. Each 7*C increase results in a 10 factor log reduction.

    Therefore, calculating PUs necessary would require you to estimate the logarithmic kill rate needed.

    In example, a hose which has been freshly cleaned with caustic and PAA may be sufficiently “pasteurized” with one PU (although it wouldn’t need it). A hose that has caked yeast residue may require more than several dozen PUs.

    I don’t ever recommend sanitation by heat, unless it’s open flame, but it can be done just fine. It seems like your method wastes a lot of energy and water, I would suggest NaOH to a pH of 12 or higher and a 15min soak. Rinse with water until pH neutral. JMHO.

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    • #3
      There are pros and cons for heat sanitation. Normally a wort line gets 80 C water for 30 min. Ideally run the hot water in a closed loop. Since the water cools down the further away from the hot water source the more likely you will have not a sufficient heat sanitation. The advantage is heat penetrates deep into the material and gaskets.
      As the previous post says first clean the hose with caustic and after the water rinse run a PAA sanitation cycle. The PAA sanitation will be safer than a hot water if you cannot ensure the 80 C throughout the whole length of the hose.
      Heat can have thermal stress on material
      Chemicals can also have a degrading impact on the hose.
      It is important to treat the hose properly. E.g. a degrading chloro butyl hose will leaving small white spots behind in your equipment. They are very smooth and almost impossible to remove. Never pack a hose with chemicals. Clean them, rinse them and store them so they can drain. Right before they are used run a sanitation cycle on the hose.
      Zee Loeffler
      888-484-6248 (US & Canada only)
      www.loefflerchemical.com
      Oliver.meinhold@vincitgroup.com

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      • #4
        hot water or steam sanitizing would always be good after cleaning with an alkali and a paa sanitizer, more or less as insurance or precautionary measure.

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        • #5
          Chemicals can't reach into every crevice. This is why we sanitize our heat exchanger, hoses, and anything that is practical with heat:


          Click image for larger version  Name:	W1320_Deniz_Bilge.jpg Views:	0 Size:	87.6 KB ID:	305706

          The MBAA practical Handbook for the Specialty Brewer recommends a 20 minute recirculation at 80C / 176F.
          Last edited by scotts; 02-23-2021, 07:51 AM.

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          • #6
            Again, no doubt the heat works, the reason I personally do not recommend it is because it (in my personal experience) exponentially increases the degradation of most seals and hose linings.

            The irony with heat is the heat itself can end up creating the micro cracking that later traps micro organisms. Avoiding excessive heat can leave the surfaces in much better condition over time, and allow for sufficient sanitation though any of the discussed methods. It is very energy heavy in terms of heating and running those volumes of water.

            To be sure, there is a very big difference between hot water and saturated steam as well. Steam is really much better because of the latent heat transfer energy happening in such a short time (almost instantly). Steam is a very effective means for sterilization but again energy intensive and damaging to certain compositions. Chemicals certainly can be damaging as well, but generally you can find compatibility.

            Surface tension is of course an important factor, however I question how well the heat from hot water can actually penetrate if the water surface tension (72mN/m) prevents the hot water from directly reaching the micro organism. Would not the rest of the space between the yellow line and the micro organism be filled with air (presumably)? Air is a poor conductor of heat, as is the typical brewery hose material. This would be the argument for hot caustic, lower the surface tension and apply the heat. Allow both the heat and the chemical to contact as closely as possible. Heating water above 85*C is going to start to precipitate calcium carbonate, so if you are trying to account for latent losses you can end up scaling over equipment if you are not careful.

            I personally favor the oxidation method for "destructing the DNA" of micro organisms, as my previous experience at the largest brewery used Ozone (O3). That is really the best IMHO as it avoids heat and surface tension issues but still reaches sterility - cost and shelf life. Ethelene Oxide was another industry favorite (research), but this isn't really practical in the brewery. PAA offers a similar oxidative principle, and I prefer to pack for 3-6 hrs, but YMMV.

            I think the real point in this thread is, research what is best for your application and never assume one method is best for everything. I obviously use hot water daily, I just think through the costs of energy, water, chemical, time and method for each given application. I also strongly advocate plating and ATP to quantify whatever method you chose so you can justify your procedure.

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            • #7
              Gotta chime in with those who don't recommend heat. Waste of energy and water and time and deteriorates soft components of your brewery--as stated above. You don't need an insurance policy if you have an effective chemical cleaning and sanitizing regimen. Personally, I like chlorine dioxide over PAA. It's easy, highly effective, inexpensive, and safe. It's also useful for washing yeast, if you feel a need to. In my many years of brewing without heat sanitation, we don't get infections. We do stick to a proven record of chemical use and incessant cleaning.
              Phillip Kelm--Palau Brewing Company Manager--

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