Airlock sucking back into carboy at secondary

[brewer_in_the_cap]

Hi all,
I brewed a Tankhouse Ale Clone 2 weeks ago and flipped it to secondary after 1 week and reaching the target FG of 1.01. A few days ago I noticed that my 3-piece airlock has been sucking Star-San into the carboy! I'm not worried about the Star-San but wonder if there's a way to stop it from continuing?

I switched out the airlock this morning and it's doing the same thing. It's getting cold here and the room temp is around 64 so that may be a factor as well?

Maybe I switched to secondary too quick, I was anxious to free up the primary to get another brew going! Also, there's no activity in the carboy (bubbles or anything) just the drops of sanitizer when it happens, which is a bit unusual to me.

Any ideas?

Thanks in advance!
NK

 

[jfk69]

As it chills down it will do that until equilibrium with room temperature is established. You could always cover it with a piece of sanitized aluminum foil for a day or so until the equilibrium is reached and then put the airlock back on.

 

[Yooper]

As it chills down it will do that until equilibrium with room temperature is established. You could always cover it with a piece of sanitized aluminum foil for a day or so until the equilibrium is reached and then put the airlock back on.

Yep!

As the beer cools, it will pull a vacuum, pulling in oxygen and star-san through the airlock. You can take the airlock off, but the easy way to prevent this is to simply package the beer, or at least don't cool the beer in a carboy.

 

[flars]

Try out the "S" style air lock. Suck back will not happen if this style is not over filled.
Buy one or two new primary buckets. End of problems due to impatience.

 

[brewer_in_the_cap]

Thanks for the help! I switched to the S-type airlock.

Could the temp difference between the primary and secondary be caused by fermentation not being complete? Everything is in the basement so the room temp is cool but stable.

Seems there's something new to learn with each brew!

 

[flars]

Racking to a secondary before fermentation is complete is one of the reasons a fermentation does not go to completion. Some of the other contributing factors are under pitching yeast, poor or lack of wort aeration, and temperature fluctuations during fermentation.