Dirty Bottle

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Joined
Aug 12, 2018
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Scarborough UK
Opened up a bottle of my latest brew last night and found it was a bit of a gusher. The others in the batch have been fine so far, so this leads me to believe that the bottle must have had a little crud left in it. What I don't quite understand, however, is why does this make a difference? What I mean by this, is how does having a little (and it will have been tiny) amount of stray yeast make such a huge difference to the carbonation levels? Is it the mix of different yeasts that make it go wild? And, if the sugars have fermented already, what is it feeding on to create such activity?
 
I’m not a scientist, but I believe the crud creates a nucleation point for CO2. Not sure why this causes gushers but it does. Same if you get a few bits of hop pellet in the bottles.
 
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If its a bottle which missed a clean then it will an infection of a hungry wild yeast, which will eat all the priming sugar. You can tell by the taste, similar to champagne, that's if there is anything left in the bottle to taste.
 
Two points here. The fact of a bit if crud, grit or hop fragments providing nucleation points for bubble formation has already been mentioned. The second is that some beer yeasts don't ferment malto-trioses very well if at all, while others do. If you think your crud might have been from a different yeast or a wild yeast then that's what's happened.
 
Hi hugh here, I see you are drinking Belgian Dubbel just waiting for mine to arrive , any comments on it? TIA.
To be honest my signature hasn’t been updated for a long long time. I think I might have a couple of bottles left but I didn’t really enjoy it.
 
Opened up a bottle of my latest brew last night and found it was a bit of a gusher. The others in the batch have been fine so far, so this leads me to believe that the bottle must have had a little crud left in it. What I don't quite understand, however, is why does this make a difference? What I mean by this, is how does having a little (and it will have been tiny) amount of stray yeast make such a huge difference to the carbonation levels? Is it the mix of different yeasts that make it go wild? And, if the sugars have fermented already, what is it feeding on to create such activity?
It will most likely have been a type of yeast or bacteria that's able to consume the 'unfermentable' sugars that the usual beer yeast can't consume. That is to say, if your beer finished at 1.010 then the wild yeast or bacteria is able to take it all the way down to 1.000 in the bottle.
 
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