Worries About Suck Back (ooh err)

[shepp]

I have never cold crashed a beer before because this is my first with a fermentation fridge.
I wondered if there is a big risk of the FV contracting and sucking the Starsan and water up the blow off tube and into my brew?

 

[The Idiot]

Try lifting the FV and see how much suck she has! I doubt it'll be 'golfball through a hose' type power, but if it gets close you know what that means: you need a longer hose!

 

[BeardySi]

Nvm , wasn't thinking...

Sent from my HTC One_M8 using Tapatalk

 

[Malcolm]

The first time I cold crashed 23L I reckon about 0.5L of Starsan and water were sucked back into the FV. Now I take the blowoff tube off and put a loose cover over the blowoff barb on the FV before I start the crash.