long fermentation

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Permalink Reply by denimglen on May 2, 2011 at 5:58pm

Airlock activity isn't a sign of fermentation it's a sign of your airlock bubbling ;-)

 

All it's showing you is the pressure inside the fermenter is higher than the outside atmosphere.

 

Check it with a hydrometer, if it doesn't change over a few days it's probably just CO2 slowly coming out of solution.

 

If it still is fermenting and the FG is higher than expected check your pitching rates, oxygenation, yeast health etc etc.

 

If it is still fermenting and lower than expected check the above and also, be aware of infection, mash temperatures and yeast selection.

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Permalink Reply by Ian on May 2, 2011 at 7:57pm

Hi Denimglen,

  Thanks for the informative reply. But if the fermentation process, and thus the manufacture of CO2 as a part of it, is no longer happening, why would CO2 be exuded from the solution with enough pressure to keep the airlock bubbling?

  I'm always a bit worried drawing samples for a hydrometer reading that I might get air into the fermentor. Maybe unnecessarily worried though.

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Permalink Reply by Matt on May 2, 2011 at 8:05pm

If the beer is warming slightly (not sure about your temp control), then dissolved co2 will be coming out of solution (solubility decreases as temp increases). I agree with Denim, take a grav and all will be revealed, if it needs to dry out a little more let it do its thing as 3 weeks isnt unheard of especially if its a biggish beer and you pitched on the low side...

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Permalink Reply by Haish on May 2, 2011 at 8:53pm

I've found S04 to be a pretty fast finisher. If your airlock is only bubbling once every 20 seconds or so then I'd say its finished. A hydro sample will reveal all...

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Permalink Reply by Ian on May 3, 2011 at 9:05am

Thanks guys. Something learned. It all makes sense now because my fermentor lives in the hallway where the heat pump is, but during the chilly periods we have had I put the heating belt on around the fermentor. So likely that has tended to drive off CO2 from the solution like you say. I'll hook out the old hydrometer.

Cheers,

Ian

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