Acetylaldehyde (AA) vacated a lager?

Discussion in 'Homebrewing' started by MisterClean, Jun 27, 2012.

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  1. MisterClean

    MisterClean Initiate (0) Jan 11, 2008 California

    So I had a baltic porter and it fermented out at sub 60 temps in the garage, but got up to the low 70s unfortunately. When I kegged and poured it a month ago, a good deal of understandable AA got in it. It has disappeared, and what a fantastic beer it is now!

    Is this normal where if a beer does have some AA, it can disappear with enough time in a beer fridge after kegging at 38F? Reason I ask, is that I will be brewing an Oktoberfest and have to use someone else's set up and cold unit. May be a bit warm is my concern, and may have the same AA in it.

    Thanks.
     
    #1 MisterClean, Jun 27, 2012
  2. VikeMan

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

    I haven't had many problems with acetaldehyde, but here's my understanding. TIFWIW.
    First, you should try to avoid racking beer that has noticeable acetaldehyde. IMO leaving it on the yeast will clear it better than anything else (and I presume that's why I haven't had many problems with it). Having said that, if you do end up with some acetaldehyde in bottles or kegs, time will often fix that, whether the beer is warm or cold. I don't think cold storage has any real advantage over warmer storage in this regard.
     
    #2 VikeMan, Jun 27, 2012
  3. JackHorzempa

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

    It is my understanding that acetaldehyde is ‘processed’ by the yeast. From Al Korzonas Homebrewing Vol. 1: “The yeast will re-absorb diacetyl and acetaldehyde (two compounds that are created during the fermentation).”

    Based upon the above understanding I think it would be ‘better’ to condition your beer at a warmer temperature vs. 38°F to permit the yeast to metabolize any excess acetaldehyde that may be present.

    Cheers!
     
    #3 JackHorzempa, Jun 27, 2012
  4. skivtjerry

    skivtjerry Pooh-Bah (1,865) Mar 10, 2006 Vermont
    Pooh-Bah

    Acetaldehyde is the classic 'green beer' flavor, as seen in Budweiser. It will always disappear in time, even at very cold temps, but as Vikeman says, a little patience with racking and cold crashing will actually save time with this issue (and diacetyl, not that you asked).

    BTW, your avatar bears an uncanny resemblance to me. Sorry about that...
     
    #4 skivtjerry, Jun 28, 2012
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