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How "final" is a final gravity reading of a static fermentation (i.e. - no stirplate)

Discussion in 'General Homebrew Discussion' started by grndslm, Jun 27, 2012.

 

  1. #1
    grndslm

    Well-Known Member

    Posted Jun 27, 2012
    My thoughts on this stem from this thread, in which I'm attempting to rephrase the original question --> Can a violent mixture of priming sugar cause a bottle of beer to overcarbonate??

    Basically, I'm wondering if a static fermentation can TRULY reach its final / terminal gravity.

    Until I decide to pick up a Black Maxx 5-gallon stirplate, it would seem to me that a static fermentation would have 0.001 of fermentable sugars left to successfully batch prime itself with a vigorous (dare i say, violent!) mixture. One with a 6-inch vortex for at least 30 seconds.

    With such a mixture, there is no doubt that each bottle will have the exact same amount of yeast and fermentable sugars... if there are fermentable sugars.

    So how many static fermentations truly have NO fermentable sugars after, say, 7-10 days primary && 21 days secondary??

    :mug:

    EDIT: Please ignore any effects of oxygenation!! This thread is strictly about reading the TRUE final gravity. If a static fermentation can't reach final gravity in 31 days, then perhaps a Black Maxx could come in handier than I had planned??
     
  2. #2
    scottland

    Well-Known Member

    Posted Jun 27, 2012
    Couple of thoughts here.

    -Depending on the yeast, static fermentation may, or may not reach it's true final gravity.
    -Per the way you phrased it: Almost every batch will have remaining fermentable sugars remaining. That doesn't mean the batch hasn't reached a true terminal gravity.

    Many highly flocculate strains of yeast will drop out of solution prior to reaching a true terminal gravity. WLP002 is a great example, especially when fermented at a cool temperature. Rousing the yeast, will usually result in better attenuation. AKA, the static ferment did not hit a true terminal gravity. There are many claims of this yeast restarting after bottling, and leading to over carbonated bottles and bottle bombs.

    With that said, just about every batch of beer will have remaining fermentable sugars. It all depends on what you mean by fermentable. Could the yeast that was pitched ferment those sugars: No, the beer has reached it's terminal gravity. But had a different yeast strain been pitched, could the final gravity be lower? Yes. Example:

    WP001/1056 might take a given beer to a FG of 1.012. That is the terminal gravity for that batch. 1.012 in this example is the absolute terminal gravity for WLP001. Had WY3711 been pitched into the same wort, it might have likely attenuated down to 1.006. Obviously WLP001 left fermentable sugars behind, as WY3711 attenuated lower. That doesn't been that WLP001 didn't reach a true terminal gravity though. No amount of shaking, stir plating, or warmth would have made a difference.

    Make sense?
     
    Netflyer likes this.
  3. #3
    Netflyer

    Well-Known Member  

    Posted Jun 27, 2012
    I agree with scottland but I have to ask the OP, "I've done all the work solely on intuition, without hydrometer." What?? and Why not use a hydrometer?
     
  4. #4
    grndslm

    Well-Known Member

    Posted Jun 28, 2012
    It's actually a quote from another thread --

    Noob question about "no-sugar" Brewferm Christmas Ale
    Just another one of the threads that peaked my interest about "bottling without priming"...

    - Optimum SG to bottle without adding primer
    - bottling methods
    - Carbonating without Priming?
     
    Netflyer likes this.
  5. #5
    grndslm

    Well-Known Member

    Posted Jun 28, 2012
    I sort of understand what you're saying...

    - Highly flocculant yeast can be roused to reach terminal gravity.
    - Medium and low flocculant yeast cannot be roused and yet will still reach terminal gravity.

    Or something like that. :tank:

    Perhaps the US-05 that we used had mutated (read: "been selected) to be a more highly flocculant yeast after a few generations??
     
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