suction at cold crash

[Cain Harland]

I had never thought of this before but of course when liquid is cooled it shrinks and will create suction into the fermenter. I have always used a blow off tube rather than an airlock and had the hose in a rum bottle half full of water with a splash of janola. That's good for fermentation and stops a vigorous fermentation blowing all the liquid out of the airlock or making a mess but at cold crash I was probably suckling janola into my beer. I have put an airlock on this time with some iodophore in it now I'm worried about infection coming in with the air. How do others deal with this?

[Peter Smith]

Make sure your fridge is real clean or cold crash in keg with gelatine under co2.

[Cain Harland]

Maybe one day I will have spare kegs, at this stage I have just the 2 to hold this brew. Hoping my gas disconnects arrive from china in time to make this my first kegged beer.

[Nathan]

Simple airlock filled with Starsan mix never had an issue allows it to "bubble" and not suck in liquid

[Cain Harland]

Good to hear I was wondering it the bubbles had enough exposure to the sanitizer or if the sanitizer evaporated out of the solution. The reason I started thinking about it is I was watching a you tube about clearing with gelatin and the guy was using a flexible "better bottle" with a check valve that only let gas out and was amazed how much it shrunk during cold crash, looked like it had been crushed.

[Nathan]

I also would like to think that there would be a good layer of CO2 still over the beer to keep it exposed from any oxygen coming in, And by the time your crashing there should be enough alcohol to fend of any nasty's 

[David M]

Had the same problem when crashing.

Used Starsan solution so not ideal but not beer tainting.

Started using longer hoses for the blow off - loop it slightly around the fermenter.

If I check it once or twice while crashing I get it before it rises too far up the tube.

Other issue I had was back pressure shooting liquid already in the tube up it and into the fermenter when I pull the blow off out of the blow off solution. Solved by spraying the connection and grommet into the fermenter with star san and pulling out the blow off tube there enough to release the pressure so the water drains into the blow off liquid.

Use blow off tubes rather than airlocks so I can fit 2 fermenters vertically in each of my fermenter fridges. Normal airlocks are to high to fit. Also often push the fermentation space with 27L batches.

I am going to try a larger diameter tube  = more volume of liquid can rise up the tube before I have probs.

[Crusader-Rob]

stasan, don't fear the foam.