Question about airlock after quick fermentation

Hey all,

Brewing my first wheat bear (Perfekt Weizenbock) from AIH. After brewing the 5 gallon batch and pitching I set the fermenter in 68 degree room. 15 hours in or so the airlock was going bat **** crazy and bubbling like mad. This kept up for 12-18 hours by my best guestimate and then it stopped. The OG was 1.067 and I pitched WLP351 yeast. The airlock bubbler piece that raises when CO2 is released is now down and resting on the inner tube. The seal is air tight on the ALE Pail, as when I push on the lid the floater raises and bubbles. I know the airlock has nothing to due with signs of fermentation, but wouldn't there be enough CO2 inside to still keep the bubbler raised up at this point, or is this normal due to the headspace inside/most of the initial fermentation being done already? Just curious...

Thanks!

 

I love when people say "I know the airlock is not a gauge of fermentation... BUT" and then ask something that leads me to believe they really think otherwise....

If you've ever noticed the center part of the airlock, the bubbler has square notches in it. When the co2 pushes up that part, it gets deflected back down by the roundness of the piece, then usually the co2 then gets dislodged through those notches, and then rises up and out of the airlock. The heavier plastic center part then usually drops back down to the "closed" position. That is if the co2 outflow is STRONGER than gravity's force on the plastic... that's why even in a supposedly tight fermenter, airlocks sometimes don't bubble, if the flow of co2 isn't strong enough to fully lift the bubbler up. ANd though I haven't noticed in awhile, there might be some on the market that don't have those slits, making them a tad heavier and probably needing MORE volumes of co2 to lift them up.



See the notches on the middle piece?



Of course what also sometimes happens is that tiny bubbles of co2 for and stick to the sides of the airlock, and sometimes the bubbler part stays up... but it is designed to, once the co2 (or oxygen if it is just offgassing o2) come out of those notched drop back down ready to burp again.

but NONE of this correlates to anything actually telling you how your beer is doing.... only a gravity readings does that.

 

After fermentation slows, the heat generated from fermentation is reduced and the pressure equalizes with the environment outside the bucket. It might even suck back a bit as the vessel cools. Pushing on the lid also forces CO2 out and then as it bends back it will suck back a bit.