reverse airflow in airlock

[socalamcor]

I just got done racking my peach melo/meth again and added in a bit of co2 to make up for the bit left in the other carboy after racking over. right now the everclear i use in the airlock keeps getting sucked into the wrong side and air is being sucked into the carboy. why does it do this, can i do anything to make it stop? ( i know there werent any major temp differences between the carboys and liquid)

 

[Catt22]

Althought counter intuitive, there almost certainly was a temperature difference and that is the source of the problem. I face the same situation when I drop my lagers down to low temps whiich causes the suck back thing. I would like to know a good solution to this problem also. I have ben keepong a carboy cap on the carboy without an airlock. Occasionally I will burp it to releive the vacuum. Once cooled, I replace the airlock. No more suck back beyond that point. I keep an eye on the airlock fluid level to be sure and it's vodka just in case. It does not take much of a temperature change to cause this phenomenon.

 

[Mattbastard]

Lemme guess, you're using those upside-down bucket air locks?

Get the "S" shaped ones, and only fill them up with about a 1/2" of vodka. They flow air in either direction.

 

[Grizz]

I know this happens to me when there is a lot of head space left and the temp fluctuates. I use Iodolpher in my airlock and there has never been a problem with my batches because of "suck back".

 

[socalamcor]

using one of the "s" airlocks. usualy dont use the three piece. also both carboys came from same room same temp. anyone know how much of a temp difference is needed to cause this or should i take that question to tech thread.

 

[ifishsum]

It doesn't take much, even an atmospheric pressure change can cause suck back. The s-shaped airlocks I have can only do this if they're overfilled - if I fill them to a little less than half full (which is where the lines are) they will pull in an air bubble instead of the liquid. Maybe yours are designed differently though.

 

[socalamcor]

not worried about the liquid getting pulled in as it is only everclear. just dont like the air getting sucked in. think another shot of co2 would be benificial?

 

[steelerguy]

What was the temperature of the CO2 you put in there? Is the temperature of the room going down? (did you just start to run your A/C?)

 

[socalamcor]

co2 cannister kept at room temp in same room the empty and filled carboy were held in. and no still using the heater at night to warm things up a bit. co2 would naturaly cool a bit even when let slowly out of the container. would warming co2 cause this?