single decoction - hard time understanding the procedure

Discussion in 'Homebrewing' started by blacklabelbrewer, May 11, 2012.

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  1. blacklabelbrewer

    blacklabelbrewer Initiate (0) Jan 27, 2011 California

    i would like to brew a lower ABV Bavarian hefe sometime soon but I am having troubles understanding the procedure. Please keep in mind i have no experience with decoction mashing so be gentle. Here is some instuctions that i would like to follow:

    Single Decoction Mash; Mash-in, 120 f Protein Rest.
    Take approx 1/3 of the total mash to decoct, run the decoction through the 120 f, 140 f, and 150 f, rests for 20 mins each, then bring to a boil and boil for 30 mins adding liquor as needed. Dump the decoction back into the main mash and adjust as necessary to hit 140F - Hefe Rest, 20 mins. Heat to 150F - Sac Rest, 90 mins. Heat to 168F - Mash-out, 20 mins.

    So does this mean i dough-in and protein rest @ 120F and let sit for 5mins and then take my first decoction? (I have read the decoction should be mostly grain with no visable water above the surface)
    After the dough-in, i pull the decoction and keep at 120F for 20 mins, then raise to 140F for 20 mins, bring to 150F for 20 mins, and then boil for 30 mins while stirring to avoid scorching the grain???
    after boiling for 30 mins i need to adjust the temp before adding to the main mash to then do a 20 min hefe rest at 140F.
    Then pull decoction and raise temps to reach 150F for a 90 min sacch rest.
    Then pull decoction and raise temp to mash out at 168F for 20 mins?


    Does this look right to you experienced BA's?
    Thanks for your time, cheers!
     
    #1 blacklabelbrewer, May 11, 2012
  2. DeutschesBier

    DeutschesBier Initiate (0) Feb 8, 2009 Maryland

    #2 DeutschesBier, May 11, 2012
  3. blacklabelbrewer

    blacklabelbrewer Initiate (0) Jan 27, 2011 California

    hell yeah, those links def helped. thanks for the leads!
     
    #3 blacklabelbrewer, May 11, 2012
  4. epk

    epk Pundit (849) Jun 10, 2008 New Jersey

    So the dotted line in those diagrams represents the decoction temp, correct?

    Hmm...We just did our first decoction brew, a double decoction (protein + two sacch rests, no mash-out decoction though), but reading this thread, I think we skipped the decoction's rest periods when we did it and went straight to a boil each time. So basically that amount of mash we decocted after the protein rest should have sat a particular temp for at least 10 mins before we brought it to a boil?

    Any ill effects of going right to boil for 20 mins (and another 10 minutes from alpha to beta saach)? And additionally, any harm by returning it to the mash tun basically all at once?
     
    #4 epk, May 11, 2012
  5. hopfenunmaltz

    hopfenunmaltz Pooh-Bah (2,635) Jun 8, 2005 Michigan
    Pooh-Bah

    The dotted lines are the decoction's time/temp profiles. The rest at ~158-160F allows the Alpha Amylase to work on the starch granules, making them easier explode in the boil. Not doing the rest will not give you the full starch conversion - maybe. I think you made beer the way you did it.

    I use a quart Pyrex cup to ladle it back in, but you cna pour it right in and stir it to even the heat out. The downside could be some hot side aeration, but that is something that has been pretty much dismissed with our current thinking.
     
    #5 hopfenunmaltz, May 11, 2012
  6. epk

    epk Pundit (849) Jun 10, 2008 New Jersey

    Okay, that actually makes sense because the boiling pretty much kills the enzymes, doesn't it? We still wound up hitting our OG more or less.
     
    #6 epk, May 11, 2012
  7. blacklabelbrewer

    blacklabelbrewer Initiate (0) Jan 27, 2011 California


    When you put it like that, it all became clear as day. Thanks again for all of the help and good questions.
     
    #7 blacklabelbrewer, May 11, 2012
  8. hopfenunmaltz

    hopfenunmaltz Pooh-Bah (2,635) Jun 8, 2005 Michigan
    Pooh-Bah

    Most of the enzymes end up in the liquid, or the thin part. Some are in the thick part, and help make the starch more available to the water, as they help eat into the small starch granules. The boiling then denatures the enzymes, but explodes the tough small starch granules.

    You put the thick decoction back into the main mash, and the liberated starch is available for conversion by the enzymes in the main mash. This is why you see a few more points in the OG when doing a decoction.
     
    #8 hopfenunmaltz, May 11, 2012
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