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  • Frame filtration issues - stuck

    Hi brewing community!

    I'm in the middle of a filtration right now and having some trouble to perform it. I began 1h30 ago and I'm just half way through it.
    We purchased a plate filter and this is my second filtration. First one was a mess as well.

    So I have 4BBL of slightly hazy undryhopped beer to filter. It's been conditioning for 3 weeks so no heavy amount of yeast.
    I picked some medium brilliant sheets, so 8-10µ. There are 16 of them, on some 40x40 frames.

    Here's what I've done.

    FV and BBT are balanced together at 1.2 bar (18 psi?). I began by performing a sanitation of the filter, hoses and pump and rinsed it with 85°C water. Once the rinse done, I pushed the hot water with hazy beer with pump off. Once hot water was out and beer fulled the system, I switched the oulet Tee to the BBT. Once pressure had been balanced, I started the pump slowly (around 12HL/h). At the beginning it went pretty well, except the output hose of the filter that was showing half beer half foam through the sight.
    But quite quickly, the output flow went to slow down, and right now, bright beer is dropping rather than flowing.

    I'm trying to understand what went wrong.
    Did I pick a too fine sheet to begin?
    Was I supposed to push hazy beer with pressure instead of pump?
    Did I turn the pomp on too soon?

    For precision, the sheets are in the right sense, I double checked.
    Right now, inlet pressure is 2.2 bar for a outlet pressure of 1.2 bar, so I guess the sheets are completely clogged.

    Does anyone have some ideas?

    Thank you,

  • #2
    do NOT push out 85 deg C water with beer. This will immediately precipitate some of the protein on the filter sheets, and denature some of the residual yeast and precipitate the proteins from the yeasts onto the sheets, helping to blind them. Cool the filter down with preferably deoxygenated chilled water at no more than 4 deg C after you have sanitised. After you have chilled down, you could blow out the water with pure CO2 before introducing the beer, whilst the filter is still cold.

    Having said all that, I suspect you are trying to filter with a grade of filter too fine for primary filtration. If you want to sterile filter, this is a two stage process - coarse to remove the bulk of the yeast and haze material, and then separate (quite possibly cartridge) filtration to "sterile" filter the now clarified beer.

    You normally want about 2 psi differential pressure across the sheets to start - but check with your sheet supplier.

    It also sounds as though you still have large amounts of suspended protein and possibly beta glucans in the unfiltered beer.


    • #3
      I think you flow rate is also far too fast. I would expect to run this size of filter at about 2.5 hl / hr (250 litres / hr). Running to fast also helps to blind the bed very rapidly


      • #4
        Hi Dick,

        Thanks for your answer !

        I do not dispose of deaerate water, neither sterile water, so I guess it will be tap water at around 14C next time, better than nothing! Hopefully it shouldn't infect the beer, I'll check with my boss the possibility of getting a sterile inline filter on the waterline ASAP.

        As I said, my sheets were given for 7-8 so just the size of saccharomyces, not a sterile filtration. Maybe I went too fine, gotta try next time on the other sheets given for 12.

        Talking about proteins and beta-glucans, I didn't think through it at first, but it might be a serious part of the problem. We are an organic brewery, thus we use organic malt, partially sourced from a local maltser who uses 6-row winter barley only. And we don't use any fining. So yes, definitely, we might have more proteins and beta-glucans than the average.

        2.5HL/h seems really low to me, it means that I should expect a 2 hours filtration for a batch anyway? Would you use the same flow rate for a 12 filtration with 20 40x40 sheets?

        Thanks a lot for your help!


        • #5
          Here's the flow rate given by the manufacturer of my sheets:

          For the 8 ones, 45L/h/m, which gives only 144L/h! Yep, I strongly messed up over there!
          For the 12 ones, 160/h/m, which gives 512L/h.

          Definitely, for the next one, I'll go on the 12 sheets, waiting to get a set for a double filtration and be able to prefilter the beer. What do you think?


          • #6
            You could use silica gel and or PVPP as neither of these dissolve, but will help remove excessive haze precursors. Unless you want to be adhering to the Reinheitsgebot and be vegan as well, you could use isinglass finings, and copper finings as the latter are generally seaweed based. None of these will remove beta glucans - for which a low temperature mash stand will be required.

            12 micron sheets will remove much of the yeast, but definitely not all, so if you want to have yeast and bacteria free beer, you will finer filters - 0.45 micron is normally used for bacteria free beer. However, unless you have the right facilities to completely sterilise everything, including, realistically, the packages, and unless you want to have silly long shelf life beer, then I suggest you stick to something like 5 micron filters for secondary which will remove the vast majority of the yeast cells, and a fair proportion of bacterial contamination.

            Only you know what shelf life you want, and what quality you want, so I would look at single pass filtration with a coarse filter to start with, and then consider double filtration if you cannot achieve the immediate clarity and microbiological stability you need. Don't forget that shelf life depends on so much more than having sterile beer ex filter - so you have plenty of other opportunities to muck the beer up!


            • #7
              I should also have said - if you are having to use towns water to cool down, then I suggest you blow out as much of this as possible with CO2 before you introduce beer as it will reduce the oxygen pickup - especially as you are only filtering small quantities. Oxygen will have a severely adverse effect on beer quality and shelf life, so the less you can introduce into the beer at this stage the better.


              • #8
                What dick said +
                I'm sure you mean sheet and plate? (A frame filter holds media like DE.) These are not filters for a high load. I would use some finings in the fv to drop most of it and use the filter to polish and remove finings. you should be able to go below 5um this way if you want. A Zero gel in the Fv has worked well for me in the past and only ads 24hrs to the process. Bio-fine could also work but has been slower. And start out with Whirlflock-T or the like in the kettle to keep hot break out of the FV. Im not a vegan but I try include them in my customer base and keep the animal products out. Besides, jelly finings are just gross, it smells like dead cow feet. HA.

                For cooling sake two things that may work: can you load and sani the filter then push it into your cold room overnight? Faster, can you loop it though your sanitized heat-ex to cool it? Both These assume a brewery not at high volume, unless you get a heat-ex just for this.
                Last edited by Ted Briggs; 03-27-2019, 08:09 AM.
                Brewmaster, Minocqua Brewing Company
                "Your results may vary"


                • #9

                  Unfortunately concerning finings, it's not about gong vegan, it's just that the organism we're working with for the organic certification doesn't allow any fining except seaweed if it's raw.
                  But my concern being definitely NOT about getting a sterile .22 filtrered beer, I should be able to manage these restrictions. The initial idea of getting a filter was to avoid excess yeast cake in the bottles as we are bottle conditioning (so 12 sheets) and to get a better stability and shelf life for the kegs (8 sheets), mostly during the hot summers of ours.

                  I'll blow the filter with CO2 for sure as I'm pretty concerned with O2 intakes. For you, no infection issue with using town water to cool the filter down?

                  Unfortunately we don't have a walk-in cold room, but the loop may work. Later this year we will have a cold water tank on the new plant, which will allow a nicer cooling of the filter.

                  Thanks both of you, especially Dick, second time you help me sorting out issues, last time was in the last brewery I used to work for where I met some CIP questions, this is much appreciated!


                  • #10
                    Aah. Bottle conditioning. I assume therefore that you are re-pitching after filtration, and calculating the additional priming sugar addition rate required.


                    • #11
                      Yep! For now we dont need to repitch but itll be an option in the future. I plan to do a cell count and viability after filtration and if I dont have at least 50k viable cells per ml, repitch the correct amount of fresh yeast then prime as usual.
                      We definitely assume that in the future well have the cash-flow to invest in a iso bottling machine, but for now...


                      • #12

                        I'm actually at the end of a 12 filtration of our amber ale, and it went great! Not even 2 psi difference at the entry of the filter since the beginning of the filtration. I strictly followed the recommendations you guys gave me so a HUGE thanks for these. I'm pretty confident for the next filtrations to come.

                        Last question but not least:
                        After this filtration, my sheets are going to be still usable. I plan to filter a pale ale tomorrow and our blonde ale next week. How can I stock and reuse the sheets without any risk of contamination?

                        My plan was to purge the filter with CO2 at the end of the filtration, at least in order to evacuate the leftover beer in there. Should I do a caustic counterflow CIP? Or just a good rinse then hot water and sanitizer next time? That last option would cook the proteins left on the sheets, I guess, so bad idea?

                        Thanks again for all these precious recommendations, they're greatly appreciated!


                        • #13
                          Quick note. As I finished my working day, I finally took the option of a caustic CIP.
                          After a good counter flow rinse, I performed a 20 min counter flow CIP with 1% middle hot caustic. Then a good rinse til the pH dropped bellow 8. I let the filter packed with water.
                          I dont have too much concerns about any residual NaOH since I plan to use PAA to sanitize the filter tomorrow and skip the hot water phase. Sounds good for you?

                          Im pretty happy with the result anyway, the beer was quite cloudy before filtration and half clarified after. Thats the goal I want to achieve for bottles, avoiding heavy yeast cake at the bottom after a couple weeks of conditioning. Bright filtration will be reserved for kegs.

                          Thanks again for your advices!


                          • #14
                            Not all filter sheets are happy with caustic but only the supplier could advise. It is possible the caustic will have weakened the sheet, but now you have done it..... I would give it a quick flush with a dilute acid to get the pH below 7 before using PAA, as there will probably be sufficient alkalinity left to neutralise most if not all the PAA.

                            If you have problems, then suggest that, assuming you have the filter sheets between plates only, so they are supported whichever way the flow is, that you run cold water backwards first, then hot water backwards at a high flow rate - around double the nominal forward filter flow rate - so in your case, approx. 5 hl / hr, then simply allow to cool down overnight, though cooling down with cold water would not be a problem. Suggest any PAA rinse is in forward flow.


                            • #15
                              Originally posted by dick murton View Post
                              I would give it a quick flush with a dilute acid to get the pH below 7 before using PAA, as there will probably be sufficient alkalinity left to neutralise most if not all the PAA.
                              PAA is effective into the pH 8 range. I have seen studies suggesting that at a pH of 8.2-8.4 PAA can still be plenty effective as a food grade sanitizer. This is why we often measure concentration by ppm instead of pH. It will not be neutralized significantly in this case, but I would still agree with a good rinse down to 7.5 or less before considering my caustic fully rinsed.

                              It has been my experience that cellulose based filter media is more suceptible to caustic damage, but that most suppliers will suggest below 2% NaOH and below 120*F to be safe in most cases. Time is usually recommended at 20-30mins max. Generally your filter media support (noryl plates, etc) will be a temperature limiting factor. I would suggest you pack with PAA as it is extremely effective over long periods and breakdown will not leave anything unpleasant. Packing with plain water is asking for unwanted growth, IMHO.