Detecting Diacetyl Problems in Advance

Discussion in 'Homebrewing' started by pweis909, Dec 9, 2015.

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  1. pweis909

    pweis909 Grand Pooh-Bah (3,250) Aug 13, 2005 Wisconsin
    Pooh-Bah

    I've got a lager going, and I have recently had some challenging diacetyl issues in other beers, where the beer seemed good in the fermenter, I racked it, and diacetyl developed in the keg. This happened to me 3x in the last few years, twice this year (using Danstar BRY-97 West Coast Ale yeast) and once about 2-3 years back using the (August Schell) American Lager Strain WYXXXX.

    The explanation, I believe, is that tasteless diacetyl precursors were present in the fermenter, which the yeast transformed to diacetyl, part of the normal activity in beers, shortly after I kegged. As the temp lowered, the yeast crashed, and they did not clean up the diacetyl (also part of the normal process).

    In all cases, I was able to clean up the diacetyl by allowing the keg to warm and adding fresh, actively fermenting yeast starter) and waiting 2-3 more weeks (maybe I didn't need to wait that long, but it's sort of pain and I decided that hurrying things along was the start of my problem).

    Recently, I heard a podcast that sort of supported this explanation and described a way to test whether these precursors are still present. It involved warming a sample of beer, I think 150 F, to speed up the conversion of diacetyl precursors to diacetyl. I can't recall which podcast or whether there was more to it than this. Can anyone help me out (either direct me to the podcast or fill me in on any details I am missing or have wrong)?
     
  2. VikeMan

    VikeMan Grand Pooh-Bah (3,067) Jul 12, 2009 Pennsylvania
    Pooh-Bah

    I think you're referring to a Diacetyl Force Test. I've heard and read about them, but have never done one. Here's one resource that explains it...
    http://www.winning-homebrew.com/diacetyl-test.html

    I chose this one because the scientist pictured on the page looks very qualified.
     
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  3. PortLargo

    PortLargo Pooh-Bah (1,831) Oct 19, 2012 Florida
    Pooh-Bah

    [​IMG] Qualified . . . indeed she looks qualified. Enjoy till the mods find this . . .
     
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  4. inchrisin

    inchrisin Pooh-Bah (2,013) Sep 25, 2008 Indiana
    Pooh-Bah

    I believe that you can also make a small starter after you hit FG and repitch a small starter on top of your batch. The new yeast will clean up after themselves, (and others), if you give them an appropriate D-rest temperature. Gordon Strong said this. A Google search of him showing cleavage is on you.
     
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  5. hopfenunmaltz

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

    Kara Taylor of White Labs gave a talk about Diacetyl and how to prevent it at the San Diego NHC this year. You can find it here if you are a AHA member.
     
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  6. JackHorzempa

    JackHorzempa Grand Pooh-Bah (3,375) Dec 15, 2005 Pennsylvania
    Society Pooh-Bah

    Peter,

    Conducting Forced Diacetyl Testing could be a good process/practice to aid you here.

    Based upon what you posted it seems that you have experienced insufficient reduction of diacetyl at the end of primary fermentation. Some homebrewers like to get their primary fermentation warmer towards the end of fermentation to assist the yeast in the ‘clean up’ process. For lager brewing this is referred to as conducting a diacetyl rest.

    Maybe this article by Dr. Chris White would be helpful to you: http://www.whitelabs.com/files/Diacetyl_Time_Line.pdf

    Cheers!

    Jack
     
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  7. dmtaylor

    dmtaylor Savant (1,149) Dec 30, 2003 Wisconsin

    Don't rack it. Yeast eats diacetyl. When you rack to secondary, you remove like 95% of the yeast, which would have otherwise cleaned up the diacetyl!
     
  8. hopfenunmaltz

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

    One thing from the Kara White talk was to get the beer warm, that forces the precursor to for diacetyl, then the yeast can clean it up.
     
  9. pweis909

    pweis909 Grand Pooh-Bah (3,250) Aug 13, 2005 Wisconsin
    Pooh-Bah

    Sorry if I didn't make it clear that I racked to the keg based on a taste test suggesting the beer was ready to rack; the diacetyl showed up later.
     
  10. dmtaylor

    dmtaylor Savant (1,149) Dec 30, 2003 Wisconsin

    Oh, okay. I hate when that happens. Keeping it relatively warm in the 50s or 60s for a couple of weeks after kegging should help. Don't do any of the cold crashing business or expect to be able to drink it immediately. Yeast still needs time to clean up after itself, even (especially) in a keg.
     
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  11. RogelioRodriguez

    RogelioRodriguez Initiate (0) Nov 7, 2015 California

    Make sure everything is cleaner than you have ever cleaned before. Lagers are unforgiving and very revealing of unwanted microbial guests :slight_smile:

    Do not treat your lager like an ale. Give it more time than necessary to work. Leave it alone, let the solitary fermenting vessel contemplate just how delightful it will be in time. 30-45 days is reasonable.

    If it showed up later it could be a simple sanitation issue, clean your faucets, gaskets, tubing etc. Also I'd try a different yeast. Safale 04 is quite forgiving but if you treat it right, it will make a very good clean lager.
     
  12. GreenKrusty101

    GreenKrusty101 Initiate (0) Dec 4, 2008 Nevada

    I respectfully disagree (at least the lager part)
     
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  13. RogelioRodriguez

    RogelioRodriguez Initiate (0) Nov 7, 2015 California

    Maybe I was lucky GreenKrusty. I heard lots of mixed feelings about 04 yeast. I tried it and had very good results. But it should be known that it was more of an American style amber lager a style I don't even regard as great, but it was astoundingly good. For German or Pilsner style lagers, probably better off with something else.
     
  14. pweis909

    pweis909 Grand Pooh-Bah (3,250) Aug 13, 2005 Wisconsin
    Pooh-Bah

    This probably would have helped. I want to reiterate that 2 of the 3 cases I mentioned above were with an ale yeast, which I treated pretty much the same as an other ale. Really caught me off guard. The earlier lager, yeah, I tried to push it out a little too fast.
     
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  15. pweis909

    pweis909 Grand Pooh-Bah (3,250) Aug 13, 2005 Wisconsin
    Pooh-Bah

    This is essentially what I ended up doing to rescue my three examples, only a bit more disjointed in time than you suggested.

    But it doesn't really matter anymore. I will not be able to erase the mental image of Gordon's exposed cleavage. You have ruined this hobby for me.
     
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  16. pweis909

    pweis909 Grand Pooh-Bah (3,250) Aug 13, 2005 Wisconsin
    Pooh-Bah

    This looks like exactly what I am looking for. The forced diacetyl rest is pretty interesting, too.
     
  17. VikeMan

    VikeMan Grand Pooh-Bah (3,067) Jul 12, 2009 Pennsylvania
    Pooh-Bah

    FTW.
     
  18. pweis909

    pweis909 Grand Pooh-Bah (3,250) Aug 13, 2005 Wisconsin
    Pooh-Bah

    Great info, everyone! Thanks.
     
  19. GreenKrusty101

    GreenKrusty101 Initiate (0) Dec 4, 2008 Nevada

    Yes, probably should get added to most contentious BA discussions/Jerry Springer shows :slight_smile:
     
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