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Question about fermentation time and general contamination.

Discussion in 'Beginners Beer Brewing Forum' started by damien666, Aug 2, 2012.

 

  1. #1
    damien666

    Member

    Posted Aug 2, 2012
    Probably been posted `100 times but here goes.

    Does the likelihood of contamination go down as the wort ages?

    I notice people here opening there buckets and looking inside yet during beginning fermentation you don;t want to open the bucket for any reason.

    Also, racking to secondary carboy. After the primary fermentation is done is it unlikely to pick up something while racking?

    How is it you can open your bucket and not get your beer sick?

    I'm considering not racking to secondary because last time I got that lacto bacteria. I am wondering if that is because I racket to soon.

    thanks gang

    DJ
     
  2. #2
    Yooper

    Ale's What Cures You! Staff Member  

    Posted Aug 2, 2012
    Usually, the risk of contamination has to do with headspace once fermentation slows/stops. If you racked to secondary (actually, a clearing vessel, not really a "secondary") and left a ton of headspace for quite a while, oxygen loving bacteria (like lacto) could take hold. But that's not common, especially for the short periods of time we're talking about.

    During active fermentation, the yeast are producing alcohol as well as co2. The co2 is a hostile environment (really, nothing can grow in 100% co2, even though your headspace will never be 100% co2) so the risk of contamination by opening a bucket or carboy to take readings is extremely low. When I make wine, I don't even use an airlock or a lid during primary- just a towel over the top to keep fruitflies out. The co2 provides a very good "blanket" to keep contaminates out. But once fermentation stops, this co2 protective layer begins to dissipate and then it's important to cover/airlock and even top up my wine to prevent contaminates like lacto from taking hold.

    For beer, it usually doesn't stay in the fermenter as long as wine, so topping up isn't as crucial. But it wouldn't hurt to purge a carboy with co2 if the beer was going to be aging long term in a carboy and there was a lot of headspace.
     
    damien666 likes this.
  3. #3
    makomachine

    Well-Known Member

    Posted Aug 2, 2012
    Beer is tough stuff, but you wouldn't know it from us anal homebrewtalkers! Open fermentation works just fine, so opening a bucket isn't going to automatically contaminate your beer. Nearly every fermentation has bacteria and foreign yeast in it. This is one of the reasons that pitching rates are important as you want the yeast strain you choose to out compete the other things that make it into your beer. We tend to take that to the extreme here, and for good reasons, but you can leave the lid off your fermentor when krausen is present, given the right environmental conditions, and your beer will be fine. Been done that way for thousands of years and that doesn't change at the homebrew level. I'm not knocking sanitation - as it's paramount to your success - just saying the occasional looking into your bucket isn't necessarily gong to cause you issues. Once fermentation is complete, the PH, alcohol, and hops protect it from yeast and bacteria to a large extent - oxygen and light become the most serious threats at that point.
     
    damien666 likes this.
  4. #4
    TimpanogosSlim

    Well-Known Member

    Posted Aug 2, 2012
    pedio and brett infections are still possible. And like others have said, o2 loving lacto can form a pellicle on the top, if there is enough o2.

    But yeah, finished beer is fairly robust.
     
  5. #5
    cwi

    Banned

    Posted Aug 3, 2012
    From what I gather, O2 loving bacteria are the ones that don't form a pellicle. The theorized purpose of the pellicle is an evolved defense mechanism to form a barrier against O2 loving things- like acetobacter.
     
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