[yso191]

Typo and incorrect word fixed.  Yike.  I always read a post 2-3 times before I hit 'Post.'

I ferment in a stainless conical - I guess I also should have said that.  I can just put a tri-clamp cap on the lid, but I think it'll just suck air through the gasket.  I hear you all say that it doesn't matter, so on to the next 'system improvement project.'  Thanks for the input.

[dkfick]

Typo and incorrect word fixed.  Yike.  I always read a post 2-3 times before I hit 'Post.'

I ferment in a stainless conical - I guess I also should have said that.  I can just put a tri-clamp cap on the lid, but I think it'll just suck air through the gasket.  I hear you all say that it doesn't matter, so on to the next 'system improvement project.'  Thanks for the input.

I don't believe it would suck air through the gasket.  Though depending on on thin your conical is I suppose there is a small chance it could implode a bit .  I have not done it with my conical (i just let it suck in air and then purge with co2 a day or so later).  With my glass carboys I typically let them have a bit of a vacuum using the breathable silicone bungs (lets things out but not in).  Even if you let in the rush of air when you take the bung out it's still better than the air sitting in there the whole time it's cold crashed...

[denny]

You always have the high-tech solution.

Whatever is the most pragmatic is almost always the correct solution.

[troybinso]

Typo and incorrect word fixed.  Yike.  I always read a post 2-3 times before I hit 'Post.'

I ferment in a stainless conical - I guess I also should have said that.  I can just put a tri-clamp cap on the lid, but I think it'll just suck air through the gasket.  I hear you all say that it doesn't matter, so on to the next 'system improvement project.'  Thanks for the input.

Can your conical take a little bit of pressure? You could connect you co2 tank at low pressure while chilling and you will have nothing to worry about.

[brewinhard]

So I too have been wondering about this for a while and have read quite a few threads on the topic.  The obvious real answer to avoid this is simply to close-transfer from primary directly into the keg, purge with CO2 and then cold crash in the keg.  I just see problems with this when using lots of dry hop pellets or even fruit additions in the last fermenter before transferring clogging up the dip tube which is a whole other problem. 

I read that some say simply to place plastic wrap over the mouth of the carboy.  Plastic wrap is gas permeable as far as I know.  Now, how fast and how much gas can permeate through the plastic wrap I am unsure of, especially over the course of a 48 hr. cold crash or so. 

Some say to use foil over the carboy mouth.  Foil will allow oxygen to ingress into the carboy when the temps inside the fermenter headspace drop simply because it is not airtight even with a rubberband. 

I myself have always used an s-shaped airlock filled with a small amount of starsan.  I have not lost any starsan into the fermenter but have noticed "air" being sucked back into the fermenter as the pressures and temps change.  I have not really noticed any major oxidation with my beers using this fashion and wonder how much O2 if any really gets into the beer itself since it is so cold and not typically agitated for the solutions to mix. 

I like the idea of the stopper except that it too will bring in oxygen when the stopper is pulled out prior to a gravity reading or transferring.  The only upside is that it may minimize the time oxygen contacts the beer as you are only spending a handful of minutes getting a gravity reading/setting up your transferring equipment vs. a 48 hrs or so of oxygen ingress.

I do not agree that the CO2 creates a blanket that protects the beer though, simply b/c as the beer cools the CO2 in the headspace is absorbed into the beer which in turn pulls the oxygen in.  I think the AHA needs to conduct a cool experiment on this one simply to see what minimizes oxygen exposure the most ($). 

Maybe a combination of all of these techniques is best and should be addressed in an experiment.  Foil + wrap?  Stopper minimizing oxygen ingress time and allowing the beer to warm up to room temps so O2 doesnt rush in when its removed?

Sorry for the rants...Just had a lot to say on the topic.   Any extra thoughts?

[HoosierBrew]

I cold crash in the keg, and when I dry hop I use a nylon paint strainer bag in the keg - no tube clogging.

[yso191]

Part of the issue for me is that I cold crash 3 times.  Once when FG is reached to precipitate the yeast, after which I dump the yeast and I raise the temp again to dry hop.  Then crash again to precipitate the hops and dump them.  I have been kegging at that point and then continuing the cold conditioning in the keg... so I guess its 2 times, the second one in conical and keg.

Anyway, I think the solution that I am going to do is this: once FG is reached just use a stopper with a valve stuck in it.  That way I can keep it closed during cooling and when I go to keg I can just attach CO2 and transfer it with a little pressure to the keg.

But again, this appears to be a solution in search of a problem.  But being the CDO type I'm going to do it anyway.  (CDO is the same as OCD except the letters are in the correct order) 

[dak0415]

Part of the issue for me is that I cold crash 3 times.  Once when FG is reached to precipitate the yeast, after which I dump the yeast and I raise the temp again to dry hop.  Then crash again to precipitate the hops and dump them.  I have been kegging at that point and then continuing the cold conditioning in the keg... so I guess its 2 times, the second one in conical and keg.

Anyway, I think the solution that I am going to do is this: once FG is reached just use a stopper with a valve stuck in it.  That way I can keep it closed during cooling and when I go to keg I can just attach CO2 and transfer it with a little pressure to the keg.

But again, this appears to be a solution in search of a problem.  But being the CDO type I'm going to do it anyway.  (CDO is the same as OCD except the letters are in the correct order)

Oooo.  I like the stopper with a valve idea!

[narcout]

I don't think this is really much of an issue, but since I ferment in 10 gallon corny kegs, I just pop the airlock (tubing attached to a gas disconnect) off before cold crashing, let a small vacuum form as the beer chills, and then pump a bit of CO2 in through the gas post.

[narvin]

You're adding just as much air when you open and throw in the dry hops.  I just don't worry about it until it's time to rack, and then I make sure the receiving keg is fully purged with CO2.

I'd also be careful about using a stopper and creating a vacuum... have you ever seen a commercial fermenter that has imploded?  Not a pretty sight.

[denny]

I read that some say simply to place plastic wrap over the mouth of the carboy.  Plastic wrap is gas permeable as far as I know.  Now, how fast and how much gas can permeate through the plastic wrap I am unsure of, especially over the course of a 48 hr. cold crash or so. 

Some say to use foil over the carboy mouth.  Foil will allow oxygen to ingress into the carboy when the temps inside the fermenter headspace drop simply because it is not airtight even with a rubberband.

I appreciate your reply, but have you ever tried either of those?  Despite the theoreticals, they work great.

[brewinhard]

I have not tried either of those Denny.  I do know many who swear by them.  I guess I am still trying to figure out how they could be better than simply using a one-piece airlock.  Do you agree that plastic wrap is probably gas permeable and that oxygen can enter underneath the foil as the temps inside the headspace in the fermenter cool down and get sucked in?

I think the real issue is this - is the amount of oxygen that ingresses with any of these techniques something to worry about, or is it negligible and not worth bothering over?  A dissolved O2 meter would be really handy for this! 

[gmac]

I read that some say simply to place plastic wrap over the mouth of the carboy.  Plastic wrap is gas permeable as far as I know.  Now, how fast and how much gas can permeate through the plastic wrap I am unsure of, especially over the course of a 48 hr. cold crash or so. 

Some say to use foil over the carboy mouth.  Foil will allow oxygen to ingress into the carboy when the temps inside the fermenter headspace drop simply because it is not airtight even with a rubberband.

I appreciate your reply, but have you ever tried either of those?  Despite the theoreticals, they work great.

I'm with you. I'm a foil topper and no issues. But I often think that perhaps I'm not worrying enough....

[yso191]

You're adding just as much air when you open and throw in the dry hops.  I just don't worry about it until it's time to rack, and then I make sure the receiving keg is fully purged with CO2.

I'd also be careful about using a stopper and creating a vacuum... have you ever seen a commercial fermenter that has imploded?  Not a pretty sight.

No doubt.

[philm63]

Anal? Do you purge your racking cane with CO2 like I do? Now THAT's anal!

Oh, and the foil on the carboy has worked for me just fine. I pull the airlock, shoot a little CO2 into the carboy before crashing and hit it with the foil - never a problem that I could detect.