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  • 2 step infusion calculation

    I am trying to calculate the temp of a secondary infusion for a 2d step. I am using a mash tun w/ no heating so all the heat must come from the water and would like rests at 144 and 154 with a ratio of .25 and .33 gl/pnd respectively for each rest. Recipe uses 430 pds malt and 1bbl water under the plates.
    I keep plugging at the formula in Malting & Brewing Science but keep coming up with T 2nd infusion =T 2nd rest. Empirically I know that the water has to be hotter than the desired rest temp. Am I doing the math wrong or what? Anyone got another formula?

    Thanks in advance, Ted
    Brewmaster, Minocqua Brewing Company
    tbriggs@minocquabrewingcompany.com
    "Your results may vary"

  • #2
    The basic mixing formula should do the trick. When dealing with mashes you need to work in Mass not volume, so in this case:
    Aa+Bb=(A+B)c

    A mass of mash
    B mass of added water
    a temp of mash
    b temp of added water
    c final water

    if you solve for c you should find *206.5Fwrong* as the answer. **Please see edit below**

    (1290lbs*144F) + (275.2lbs*b) = (1290lbs+275.2lbs) * 155F

    So after heat loss during transfer you are probably talking about boiling water.

    FYI the new MBAA Handbook of Basic Brewing Calculations is a great resource for this kind of stuff. Cheap too.

    Good Luck

    * My apologies! I made a mistake in the use of this equation! The basic mixing equation only works if the materials being mixed have an equal impact. In the situation being considered a pound of water has a different impact than a pound of malt. This is defined by the heat capacity which water happens to be 1 and mash is approximately .4 (depending on moisture levels). So you will need to calculate the overall mash heat capacity first.

    To find the mash heat capacity:
    ((.4*grain wt)+current water weight)/total weight
    so
    ((.4*430lbs)+860lbs)/1290 = .8

    and then use

    added water lbs = ((mash heat cap.*mash wt) * (goal temp-present temp))/added water temp-goal temp

    so
    275.2lbs=((.8*1290)*(154-144))/X-154

    solving for X gives you 191.5F

    Hope that works a little better!
    Last edited by Tbrew; 05-04-2004, 06:34 PM.

    Comment


    • #3
      Originally posted by Tbrew
      The basic mixing formula should do the trick. When dealing with mashes you need to work in Mass not volume, so in this case:
      Aa+Bb=(A+B)c

      A mass of mash
      B mass of added water
      a temp of mash
      b temp of added water
      c final water

      if you solve for c you should find 206.5F as the answer.

      (1290lbs*144F) + (275.2lbs*b) = (1290lbs+275.2lbs) * 155F

      So after heat loss during transfer you are probably talking about boiling water.

      FYI the new MBAA Handbook of Basic Brewing Calculations is a great resource for this kind of stuff. Cheap too.

      Good Luck
      By adding boiling water to already hydrated mash,...aren't you de-naturizing a substantial percentage of conversion enzymes?
      (affecting potential carbo loss?)

      Is there a cross calculation accounting for this maybe?

      Comment


      • #4
        Yes, you will be denaturing some enzyme. If you are an all malt brewer this should not be a problem. In all malt mashes you have roughly 3 times the enzyme you would need (especially if using N. American malts) and thus ruining up to 2/3rds is not a problem. Same situation with decoction mashing and the end result is A'OK there too.

        Affect would be less the better your mixing.

        Comment


        • #5
          2nd Infusion problems

          Thanks for your help
          After further work I came up w/ the same thing- boiling water from the kettle.
          As for enzyme loss that is a concern. The whole reason for this is to get a more fermentable wort thus drier beer. I hope that my plan to underlet the 2nd infusion and stir like crazy will off set this.
          Ted
          Brewmaster, Minocqua Brewing Company
          tbriggs@minocquabrewingcompany.com
          "Your results may vary"

          Comment


          • #6
            If the aim is to get a higher attenuation, why not experiment with a yeast with a high attenuation. If it is ale brewing my experience with Lallemand nottingham dry yeast is that with pale ale malt and single step infusion between 63 and 69 degrees celsius you will reach an attenuation between 79 and 82 %, with a OG up to 1056.

            Comment


            • #7
              If you want a more fermentable wort, mash in at a slightly lower temperature until you achieve the profile, but probably not less than 64 deg C initial mash temperature. Try dropping the mash temperature ).5 deg C at a time, by dropping mash liquor temperature, probably by 1 deg C.

              Check you yeast viablility, wort oxgenation and yeast food, particularly zinc. Low viability yeast will ferment poorly.

              Cheers
              dick

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