Does cold crashing prevent bottle bombs?

Discussion in 'General Brewing Discussions' started by The Green Man, Nov 1, 2017.

  1. The Green Man

    The Green Man Active Member

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    #1 The Green Man, Nov 1, 2017
    Last edited: Nov 1, 2017
    Hello Brewers. I have a dilemma. My oatmeal stout has under attenuated a little (63%), but tastes great. Its only had 4 days in the fv, but I would happily drink it now! Thanks to shoddy mashing my OG was lower than I was hoping. So, I'm worried about losing something with more attenuation.
    I used S04 and my temp in my ferm chamber is 14c 57f now (its a wine cooler, so pegged to ambient temp). As the stout tastes great already, should I drop my chamber temp to 4c 39f to cold crash and bottle early?
    Are there any negative consequences I should be aware of i.e bottle bombs etc...
     
  2. Mark D Pirate

    Mark D Pirate Well-Known Member

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    Cold crashing won't prevent bottle bombs , simply put some strains can't eat all of the sugars in wort / beer or will doze off before the job is finished .
    you can cold crash and bottle now if you like but once your beer has carbonated in the bottle then for safety's sake you chill every bottle down to stop the yeast munching away and farting out yet more bubbles .
    Myself i'd be leaving the batch sit a little while longer and raise temps to ensure yeast eat everything they can then bottle
     
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  3. thunderwagn

    thunderwagn Well-Known Member

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    You could have bottle bombs if fermentation isn't complete. Take a gravity reading and another in several days. If it remains the same, you should be able to bottle. You could also try bumping temps up a bit to see if you can get a bit more out of it.
     
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  4. Trialben

    Trialben Well-Known Member

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    3rd this green man it aint worth the risk:eek:!
    Let it ride out do as above post mentioned and if you like it here at this attenuation with this sweetness maybe try some lactose sugar in next batch of this beer like 200g worth that will remain unfermented and pissibly give you the same results without risking explosions:).
     
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  5. oliver

    oliver Well-Known Member

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    on the contrary, I found that cold crashing too hard can result in low carbonation because not enough yeast is being pulled into the bottle. but like everyone said, it's about the gravity of the beer and what kind of yeast you're using that goes into the bottle that determines carbonation levels.
     
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  6. J A

    J A Well-Known Member

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    All the bottle bombs I ever had were with S-04. It just takes off too hard and drops too fast. I learned to swirl and raise temps and wait it out. You can make some great beer with that yeast, but it ain't over 'til it's over. :)
     
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  7. The Green Man

    The Green Man Active Member

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    Thanks brewers, sage advice as always. The fermenter is now out of the cooler and slowly warming back-up..The world doesn't need more explosions.
    It's already bubbling again...not that that is the single signal of active fermentation...It ends up too thin and dry, I'll have to put it down to experience.
    Appreciate the help fellas. Cheers.
     
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  8. J A

    J A Well-Known Member

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    The airlock will bubble as it warms up. That's just the volume of liquid and air trapped in the carboy expanding with rising temp and creating pressure that bubbles the "air" out. You'll need to warm it back up to 72F or so and swirl the heck out of it to rouse it after putting it to sleep. You might wait to see if it goes without stirring, but I would swirl to get the process moving.
    Even though S-04 and some other yeasts will go insane and do most of their work in the first 24-48 hours, it's best practice to assume about a week in fermentation is minimum.
    If you keep the temp low at first, like pitching at 65 and dropping to 62 or so, it'll slow the initial fermentation and allow the yeast to be a little more thorough. Raising pretty quickly after the first 36 to 48 hours keeps things going and provides a good environment for the yeast to stay active and in suspension. Even then, I still give it a swirl once a day for several days until I'm convinced it's down to the clean-up phase.
     
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  9. Nosybear

    Nosybear Well-Known Member

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    Actually it's about the residual sugar or contamination by an organism that can digest complex sugars that Saccaromyces can't. Most bottle bombs are caused by bottling too quickly, leaving more sugar than expected for the yeast to digest, or by contamination. A third, unlikely reason would be adding too much priming sugar, but I suppose it could happen. To avoid, I monitor fermentation using my refractometer and my correction spreadsheet. If the gravity holds steady within a point or two above my expected OG for three days, I assume the fermentation is done. After that, I still condition for a week or two before bottling. That ensures that I don't have any unexpected malt sugar left in the beer for the yeast to digest. Contamination: Sanitize. Priming sugar: If it looks like it's too high, recalculate and remeasure. Those three things should reduce the risk of bottle bombs to near zero. You can never eliminate the risk but you can reduce it to the point you don't fear walking into your basement....
     
  10. Mark D Pirate

    Mark D Pirate Well-Known Member

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    Or you can just invest in kegs ....good luck getting one of them to go boom !
     
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  11. Nosybear

    Nosybear Well-Known Member

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    They will, if you overcarb enough. With good technique, the odds of a bottle bomb are minimal. I'd guess my score is about 2 in over 1,000 bottles.
     
  12. jmcnamara

    jmcnamara Well-Known Member

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    After just one or two, I've learned to go on the conservative side in terms of volumes of co2 and amount of priming sugar. Much rather a slightly flatter beer than a broken bottle or overflowing a glass with head

    Or, just put the bottles in a cooler or other enclosed space for a while. Makes clean up a lot easier if they do bust
     
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  13. Mark D Pirate

    Mark D Pirate Well-Known Member

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    I
    was just being cheeky ....
    When I first started making horrible beer from pre hopped kits with a kilo of table sugar the instructions said bottle after 7 days .
    I had thought bottle bombs were just normal along with the shocking hangovers , when I started up again the internet soon showed me what I was doing wrong and not had a problem yet
     
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  14. Gledison

    Gledison Active Member

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    I think if you know your OG , measure the actual gravity and you will know how much sugar still in there (roughly :p). if you are about 0,5% of the FG you could use this rest sugar for carbonation. But yeah, still risky. Well, lern from it. if its to dry in the end, do a hihger mashing temp or add some other unfermentable Sugars :)
    good luck
     
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  15. Nosybear

    Nosybear Well-Known Member

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    ...or use Plato for your gravity, which roughly approximates the amount of dissolved sugar.
     
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