OK to plug carboy when crash cooling?

I am looking to start crash-cooling my beers and possibly adding gelatin if needed in order to start getting better clarity. I was thinking of just taking out the air lock and drilled stopper, and replacing with a sanitized non-drilled rubber stopper. Has anyone done this? It seems appropriate since no gas will be going out, but will instead be sucking in. I am just concerned that the internal suction could cause the carboy to possibly "implode" if it gets strong enough. If anyone with experience has any insight, it would be greatly appreciated!

The carboy isn't likely to implode but it might suck the stopper into it. Have you thought about how to remove a solid stopper from inside a carboy?

Put on a stopper with an airlock. If you don't put a lot of liquid in the airlock it won't be sucked back into the carboy and if you use a sanitizer like Starsan in it the suckback won't be harmful to your beer even if you do get a little.

The stopper is the same stopper as the one that holds the airlock, it is just not drilled. So technically if this could suck into the carboy, so would the airlock. I think I will just give this a try and see how it works out. Te idea of any liquid suckback really bothers me.

Bisco_Ben said:

The stopper is the same stopper as the one that holds the airlock, it is just not drilled. So technically if this could suck into the carboy, so would the airlock. I think I will just give this a try and see how it works out. Te idea of any liquid suckback really bothers me.

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Bad idea, the non-drilled stopper WILL get sucked back into the fermenter.

The reason the drilled one with the airlock doesn't is because the airlock allows two-way exchange of air; yes, air CAN go in to the carboy through the airlock (sometimes sucking liquid back in, in the process).

Just use a small amount of Starsan +water solution with an airlock. It'll be fine. I do this all the time.

MC

This is what you need. Best of both worlds!

http://www.keystonehomebrew.com/shop/7-silicon-bung-ventilating-carboys.html

Use an air lock with vodka in it.

Use an S type airlock.

beergolf said:

Use an S type airlock.

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This, with just enough water to cover the bottom bend.

Has anyone ever actually had a rubber stopper suck into the carboy? I just refuse to believe that this is possible. I couldnt squeeze it through the neck of a carboy if I tried as hard as I could. Has this actually happened to someone or is this another homebrewing myth?

Either way, I am going to run a few tests to see which works the best between the plug, 3pc airlock and S-airlock. I will post my results for anyone who is interested.

I crash cooled and forgot to switch out the blow off. Ended up with a half gallon of sanitizer on top of my beer. Not cool!

Now just a small amount of it in an airlock is the way to go.

Lots of people on the web seem to be asking about how to get a stopper out of their carboy. And if it doesn't get sucked in, and carboy is glass, well, these aren't exactly pressure vessels.

Just sayin'. It's your equipment, and your choice. Just be sure to be informed.

@Latium, I completely agree about the pressure aspect. The carboy imploding is my only real concern with using the stopper. I am just going to crash cool a carboy filled with water and measure exactly how much water (or in my case vodka) gets sucked back. if it is truly that minimal, I guess I will just stick to airlocks to be safe. But to be honest, suckback really bothers me and has kept me from crash cooling my beers for the 4.5 years that I have been brewing for so far.

ALSO, the only stories about the stoppers falling into the carboy did not involve the sort of stopper that I am using. The "universal" stopper I have WILL NOT get sucked/pushed in, no matter what force is being applied.

I was cleaning my carboy by vigorously shaking it back and forth with soapy water inside, while using a perforated stopper as a top. It pushed in until below lip of carboy. Had to use a screwdriver to get it out - putting it through where the airlock goes. It didn't take much to get it in that far, and it almost went all the way in. There is no way of getting a stopper out of a carboy. Do what they say. Use an airlock. I had a mead sucking air back into the bottle, because I left the door open, and the temp went down. It would definitely pull a stopper in under right conditions.

Why not plug one of the cheap sanitary air filters into the stopper. That would let the air pressure equalize and keep the incoming air clean. with enough headspace of CO2 the small amout of O2 shouldn't hurt. Just a thought

http://morebeer.com/view_product/16797/102363/Sanitary_Filter

Bisco_Ben said:

Has anyone ever actually had a rubber stopper suck into the carboy? I just refuse to believe that this is possible. I couldnt squeeze it through the neck of a carboy if I tried as hard as I could. Has this actually happened to someone or is this another homebrewing myth?

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It's not a myth. When I brew in the winter in SC, I bring my sanitized carboys from inside the house to outside, while they are donning a non-perforated stopper. They usually get sucked in partially while the carboys are waiting to be filled. And this is from only 10-15 minutes outside, with a differential of about 20F (68F inside, 48-50F outside).

MC

I have cold crashed with a stopper. No problem. I read several threads where people did the same before attempting. I also tried a plastic bag with a rubber band to see how much it would suck in. Very little deflation. I think the pressure concerns are overstated. But watch my next stopper get sucked in...

Get yourself a nice clean handkerchief. Fold it in half then half again. Lay it over the top of the carboy and secure it with a rubberband or a nice piece of string. The only thing that will likely get sucked into your carboy, other than filtered air through the handkerchief, will be lint from the handkerchief.
Problem solved.

If I am cold crashing a beer I always use the s-type airlock and have never had suck back. I keep a couple around just for this reason. I don't use them for primary fermentation because they are a pain to clean if you get krausen in them.