Rookie mistake: oxidation while fermenting?

Discussion in 'Homebrewing' started by ChickenBear, Jun 24, 2016.

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  1. ChickenBear

    ChickenBear Initiate (0) Jun 22, 2016

    A friend recently donated a 6 gal. carboy to our homebrew setup, but we didn't think to check the cork. It wasn't until the yeast had been pitched and we were about to seal the carboy that we noticed the stopper didn't fit. We used foil tape to temporarily seal the opening of the carboy until we could find a new cork.

    Within the first 24 hours, the pressure inside the carboy broke the foil seal, leaving the fermenting wort exposed for 5-8 hours (room temp ~75 F). During that time the yeast had expanded out of the opening of the carboy and receded back to a normal level. 36 hours after adding the wort to the fermenter the cork and airlock were replaced.

    This is my second time brewing, so I'm not sure what to expect here. Is it likely that the air exposure will cause a significant impact in taste/quality of the beer (dunkelweizen)? What should I look for in regards to contaminants?
     
  2. ssam

    ssam Pundit (997) Dec 2, 2008 California

    First of all, you shouldn't ever seal the carboy. Buy an airlock that fits your carboy.

    Hopefully it is fine, but you're biggest concern should be infection. Oxidation risk was probably minimal because active fermentation will produce a lot of CO2 to push out any oxygen right now. Bacteria and wild yeast may have gotten in your fermenter, if you notice a pellicle form (it looks like a fuzzy bubbly fungus) on the top of your beer you have an infection. If that happens you might get a sour dunkelweizen.

    Next time this happens, don't seal the carboy or, as you observed, the pressure will bust through your seal. You can cover the opening of your carboy loosely with a crimped piece of sanitized foil if you don't have an airlock. Don't cover it tightly otherwise pressure will build and blow it off. CO2 will still be able to escape but bacteria won't come in due to their inability to turn tight corners (weird, but true).

    Also, since you mentioned the yeast went through the opening, you may want to get blowoff tube setup. If your airlock gets clogged during a vigorous fermentation, it will build pressure and explode a terrible mess onto your ceiling. A blowoff tube will lessen that risk.
     
    #2 ssam, Jun 24, 2016
    Last edited: Jun 24, 2016
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  3. JackHorzempa

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

    Oxidation is not a concern as long as the beer is fermenting.

    The risk of infection is dependent on your brewing environment. I have read where some homebrewers conduct open fermentations. The aspect that I would personally be most concerned about is flying insects like fruit flies. Fruit flies are covered in bacteria and if they get into the beer the bacteria could result in off-flavors in the beer (i.e., an infection).

    Since you are now sealed up you are now protected. It is possible (likely?) that nothing got into your beer that will create an issue. Just let the fermentation 'ride' and think happy thoughts.:slight_smile:

    In the immortal words of Charlie Papazian: RDWHAHB (Relx, Don't Worry, Have a Homebrew)!!

    Cheers!
     
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  4. VikeMan

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

    I'd say it's not much of a concern while the fermentation is roaring along, but more of a concern once it starts to wind down. In OP's case, it may well have still been ripping along, given the timeline he described.
     
  5. Beejay

    Beejay Pooh-Bah (2,559) Dec 29, 2008 Virginia
    Pooh-Bah

  6. GetMeAnIPA

    GetMeAnIPA Pooh-Bah (2,559) Mar 28, 2009 California
    Pooh-Bah

    I would be as concerned about the temp. If the ambient temp is 75 that means the wort could be as warm as 80.
     
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  7. VikeMan

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

    Yeah, that's a little toasty. OP is making a Dunkelweizen, so it's possible he's using a hefe strain that won't go as far off the rails as most other strains at high-ish temps. But I'm not sure, as I've never pushed a hefe strain that high.
     
  8. PapaGoose03

    PapaGoose03 Grand High Pooh-Bah (6,057) May 30, 2005 Michigan
    BA4LYFE Society Pooh-Bah

    Welcome to the BA site and to the Homebrewing forum, ChickenBear. Those are all good answers above to your question, so I won't add to them. However, to make your brewing session a more complete learning experience, I'll mention that your beer is fermenting at a temp that is too warm for being ideal, and the extra warmth likely was a partial cause for the intensity of the fermentation.
     
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