Why are my airlocks working backwards?

[JBrady]

The other day the airlocks on both of my better bottles were working backwards to the point of dripping water back in the beer.. I've never seen this happen before and was wondering if you guys knew what was going on. Both beers had also been in the fermenters for at least two weeks, so its safe to say fermentation was completed. Any info would be helpful.

 

[riverfrontbrewer]

Is your temp going down?

 

[JBrady]

yea from 68 to about 63 with the sudden temperature drop the last few days

 

[Yooper]

yea from 68 to about 63 with the sudden temperature drop the last few days

That would be the cause.

 

[Brewsmith]

Fermentation is done so no more CO2 gas is coming out, and the temperature went down, making the volume shrink, creating a suction.

 

[TXBeowulf]

An airlock allows one-way movement of gas from an area of higher pressure to an area of lower pressure. If yours is letting air in, the air pressure outside your fermenter is lower than inside. The sudden temperature drop would account for this, though I would think it would have to be pretty steep.

 

[JBrady]

thanks all, that pretty well answers our question

 

[jmansfield]

Suck-back. Could be a bad problem - contaminating your beer. I use vodka in my airlock to help avoid contamination (not that I really want any vodka in my beer, it is just better than some nasty water or iodophor). When your beer stopped producing CO2 it was at a certain temperature (let's say 70 F). It was also at a certain pressure, probably about 1 inch water column. For some reason the beer started cooling, let's say to 65F. This causes the CO2 molecules that are trapped inside to start contracting and voila - the pressure inside your fermenter dropped slightly below atmospheric until it sucked in some and equalized.

 

[springer]

An airlock allows one-way movement of gas from an area of higher pressure to an area of lower pressure. If yours is letting air in, the air pressure outside your fermenter is lower than inside. The sudden temperature drop would account for this, though I would think it would have to be pretty steep.

Huh? The air pressure outside would have to be higher then inside.

I get this when I cold crash so I just use tin foil till it stabilizes.

 

[TXBeowulf]

Huh? The air pressure outside would have to be higher then inside.

I get this when I cold crash so I just use tin foil till it stabilizes.

Exactly...

 

[springer]

An airlock allows one-way movement of gas from an area of higher pressure to an area of lower pressure. If yours is letting air in, the air pressure outside your fermenter is lower than inside The sudden temperature drop would account for this, though I would think it would have to be pretty steep.

Huh? The air pressure outside would have to be higher then inside.

I get this when I cold crash so I just use tin foil till it stabilizes.

Exactly...

Am I reading your post wrong ?

 

[TXBeowulf]

No, I had it backwards and then read what I meant instead of what I said the second time. It's what I get for trying to keep up with forums on the boss' time

 

[springer]

No, I had it backwards and then read what I meant instead of what I said the second time. It's what I get for trying to keep up with forums on the boss' time

I had a beer at work so i thought it may be me.

 

[GilaMinumBeer]

You put them in backwards.

 

[IceFisherChris]

You put them in backwards.

Fermentation could be going backwards too