Announcement

Collapse
No announcement yet.

DO Pickup during filtration

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • DO Pickup during filtration

    Hi guys,

    I'm wondering what is a good target for DO pickup during filtration. Right now we are seeing about 50 ppb DO change before and after our filter, a 3 sq m with dosing pump. That seems pretty high. We are purging the filter with CO2, and purging the dosing tank with CO2 during filtering. What are some of you seeing for DO pickup during filtration?
    Linus Hall
    Yazoo Brewing
    Nashville, TN
    www.yazoobrew.com

  • #2
    That's a really big pickup off the filter. Should be 10 ppb or less of pickup, and preferably less than 5. Where are you taking the DO readings from? Bright tank or directly off the filter? What kind of sample ports are they? What grade of DE are you using?

    Comment


    • #3
      Hi Linus,

      Is that a fairly steady pick-up during filter runs? Or is that tank-to-tank? Has the pick-up got worse or been steady for some time?

      My first thought is to check things like joints, pump seals, etc. as these can bleed air in without any signs of liquid weep out. Air, at 20% O2, will read around 9ppm (ie. 9000ppb) on a DO meter set up for liquid analysis, so it doesn't take a lot of air to give you 50ppb rise.

      Also, any high points in your system that might not be getting purges with CO2?

      If you have deaerated water available you can pack the filter route with it then push through with beer if you have any worries about air pockets.

      Comment


      • #4
        DO pickup

        Two questions to consider.
        1) How exactly are you purging?
        -Are you pressurizing and then blowing down?
        -once, twice, or three times?
        -Are you filling with sanitizer and then pushing it out with CO2...

        2) If you do any unfiltered beers, what is your O2 pickup during transfer.
        -If it is FAR less, than I would look at the filter. If not, then the filter is not your problem. The problem lies either in your purging procedure/peripheral procedures.

        Good luck.

        Cheers,
        Jeff Erway
        La Cumbre Brewing Co.

        Comment


        • #5
          If you are using kieselguhr, you really need to bubble pure CO2 or nitrogen through the slurry, both for a decent time before starting to dose, and at all times during dosing. This is often forgotten about, and can make a huge difference.

          If you are not using dearated liquor to precoat the filter, then the small quantity of water left in the filter (assuming a horizontal leaf filter) or large quantity (plate & frame or candle) will add a large amount to the final beer if your run lengths are small, i.e. considerably less than the maximum capactiy of the filter.

          Cheers
          dick

          Comment

          Working...
          X