Raising fermentation temp/cold crashing

Discussion in 'Homebrewing' started by briggssteel, Apr 10, 2014.

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  1. briggssteel

    briggssteel Initiate (0) Apr 8, 2010 Ohio

    Hey all. I was listening to The Brewing Network and it raised a couple of questions. I was hoping to get some confirmation/elaboration if you guys wouldn't mind.

    The first question is do you guys recommend raising the temperature at the end of fermentation. I know Jamil suggests this but he isn't very specific with how to know when fermentation is almost done and how high to raise it. I'm doing a kolsch right now that had been fermenting at 59. Yesterday I set my temp controlled fridge to 62 and letting it rise on it's own. It was on it's 4th day from pitching and the krausen had started dropping so I assume that's "near the end of fermentation". I plan to do 3 more degrees for two more days until I hit 68. Is this adequate? What do you all suggest?

    The other question I have concerned cold crashing and oxidation. I plan to lager this beer at the end of 3 weeks for 1 month. On The Brewing Network they mentioned cold crashing the beer will suck whatever is in the airlock and O2 into the beer. I plan on dropping it 5 degrees a day until I hit 35. I don't know if this constitutes as "cold crashing" but I definitely don't O2 in my beer. Jamil suggests cold crashing in the keg, but I bottle condition my beers so that won't work. I did some reading and someone said after fermentation you could take the airlock out and seal it with foil before cold crashing so O2 doesn't get in solution. It may be unfounded, but I have concerns about sealing up a glass carboy that had been producing CO2

    It's funny how as a brewer you think you knew how things worked and then you learn something like that cold crashing advice that you never knew before. Thanks in advance.
     
    #1 briggssteel, Apr 10, 2014
  2. JohnSnowNW

    JohnSnowNW Initiate (0) Feb 6, 2013 Minnesota

    I nearly always raise the temperature toward the end of fermentation, usually around 68-70°. I leave it at that temp until I keg.

    I don't cold crash in the fermentor, so I can't really answer that question.
     
    #2 JohnSnowNW, Apr 10, 2014
  3. JackHorzempa

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

    I do not raise the fermentation temperature towards the end of fermentation. As long as you remain within the recommended temperature of the given yeast strain it will complete its ‘job’ without issues. If you want to raise the temperature, that will do no harm.

    I cold crash my lagers (with an airlock in place) all the time. I have brewed 70+ lagers this way and I have never suffered any issues (no oxidation). Based upon my personal homebrewing experience I would suggest that you keep the airlock in place and cold crash away.

    Cheers!
     
    #3 JackHorzempa, Apr 10, 2014
  4. WelshBrewer

    WelshBrewer Initiate (0) Mar 17, 2013 Oregon

    Don't know what kind of airlock you are using but I use the "S" shaped ones and put vodka in them and no matter what I do if the liquid level in the airlock is correct it "cant" get back into the beer. Cold Crash Away
     
    #4 WelshBrewer, Apr 10, 2014
  5. briggssteel

    briggssteel Initiate (0) Apr 8, 2010 Ohio

    So how do you know when you're near the end of fermentation? Is it from a hydrometer reading when you're close to final gravity, a time thing (4 days after pitched yeast for example), or can you tell by looking at it? Also are you just putting it at 68-70 all at one time or are you gradually raising it (a degree a day for example)? I guess I'm trying to find out people's methods of doing this.
     
    #5 briggssteel, Apr 10, 2014
  6. JohnSnowNW

    JohnSnowNW Initiate (0) Feb 6, 2013 Minnesota

    I use a chest freezer to ferement, so I just raise the temp on my digital temp controller, and let it rise naturally. As for when, I basically do it 5-7 days after the majority of fermentation has completed, which is usually denoted by fallen krausen and air-lock activity. I don't normally take any measurements until after 3 weeks, or before I transfer to secondary.
     
    #6 JohnSnowNW, Apr 10, 2014
  7. briggssteel

    briggssteel Initiate (0) Apr 8, 2010 Ohio

    I'm actually using the other type of airlock. I'm not opposed to using an S shaped one. I just don't know if I'll make it to a home brew shop to get one before I lager it as it would be out of my way.
     
    #7 briggssteel, Apr 10, 2014
  8. JohnSnowNW

    JohnSnowNW Initiate (0) Feb 6, 2013 Minnesota

    To clarify, that was supposed to be 5-7 days after the start of fermentation, when the bulk of fermentation was complete.
     
    #8 JohnSnowNW, Apr 10, 2014
  9. WelshBrewer

    WelshBrewer Initiate (0) Mar 17, 2013 Oregon

    I wouldn't worry too much I don't think you are going to have a problem, switch the water or whatever with vodka if some gets in there by chance there will be no worries.
     
    #9 WelshBrewer, Apr 10, 2014
  10. AlCaponeJunior

    AlCaponeJunior Grand Pooh-Bah (3,452) May 21, 2010 Texas
    Society Pooh-Bah

    Why?

    the concerns with cooling aren't at all exacerbated by CO2 being in there. CO2 is perfect for being in there, in fact, because it's heavier than air, it sinks to the surface of your beer, protecting it from oxygen.

    Sounds like one of those fancy airlocks and some vodka are in your future. But please, if you make bloody mary's, make mine spicy, wtih the salad, and don't use cheep vodka. :grinning:
     
    #10 AlCaponeJunior, Apr 11, 2014
  11. VikeMan

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

    While there will certainly be an occasional collision between CO2 and O2 molecules, the CO2 will not stop all the O2 from reaching the beer. It would be nice though. I could use a lot less CO2 when purging bottles.
     
    #11 VikeMan, Apr 11, 2014
  12. briggssteel

    briggssteel Initiate (0) Apr 8, 2010 Ohio


    Well I already have vodka in it, but it's not the S type airlock. At the end of my 3 week conditioning period I might just take the Airlock out, put some foil over the bung then start dropping the temp. I suppose if vodka did get in though it would just be an "imperial kolsch. " haha
     
    #12 briggssteel, Apr 11, 2014
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