Cold crash, air lock sucking

I'm cold crashing about 38F temp differential at 3F

I fill 3 peice airlock to the line. 3 hours later it drinks half of it.

I have refilled it 3 times in the last 24 hours everytime I check it stops around the same spot. Last time I filled to the line was at 4PM checked 20 min ago and bam it drank a shot. I'm afraid of leaving it low because I dont want it to suck in air but wtvr.

I've read stopper..I have bucket dont think stopper will work too well.

S shape airlock..I didnt read enough about it but what do you guys think?

should I just see if the airlock gets sucked dry? Or is that terribly bad?

Can you pull out the airlock and replace it with a solid bung? The reason it's sucking in is because of the temperature dropping inside the fermenter and pulling a vacuum. If you take out the airlock and replace it with a solid bung (or even some sanitized foil), that will be a quick and easy fix.

I dont have a solid bung, but I do have foil. How do you go about using foil? Ill get solid bung for next time tho.

boss429 said:

I dont have a solid bung, but I do have foil. How do you go about using foil? Ill get solid bung for next time tho.

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1. Sanitize foil
2. Put foil over top of carboy

You aren't looking for an airtight seal, just something to keep stuff from falling in.

well bone dry 3 pc airlock would do the same wouldnt it?

Ya unless you've got it hooked to a CO2 regulator, you're going to suck air in when cold crashing. If you diligently refill the airlock you might as well pour it straight into the fermenter, you're not accomplishing anything, the 3 piece airlocks don't work backwards.

Maybe its just me, but creating a vacuum with a solid bung on in a large glass carboy does not seem like a good idea. Especially if your cold crashing more than 3 deg. The beer should be fine in terms of risk of infection if its covered, and oxidation should be minimal (the change in volume isn't very large). The beer should reach the crash temp within a few hours where it will stop contracting and also stop pulling a vacuum. You can reapply the airlock at this point and let it sit for the desired crash time.

I use a "blow-off" tube, just make sure it's long and the liquid container is below the top of the fermentor somewhat, after a day or two simply lift the hose from the container and drop it back in. Call it a "suck-up" tube, or an "anti-suck-up" tube, or a "no-suck-back" tube, etc, it's just a blow-off working in reverse.

Keep on sucking my friends

boss429 said:

well bone dry 3 pc airlock would do the same wouldnt it?

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Yeah, if you covered the top of the dry airlock with foil. You want to cover the carboy opening.

So I'm not understanding the whole suck-up tube idea. I understand how it works, but when you pull the tube out of the container to let the water out, the same volume of air enters the tube and carboy.

ridnpowder said:

So I'm not understanding the whole suck-up tube idea. I understand how it works, but when you pull the tube out of the container to let the water out, the same volume of air enters the tube and carboy.

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Yea, but hopefully, no contaminated fluid. If you are worried about a little air getting in, use a longer tube, coil it up, make it 2 miles long. Just keep it below the fermentor, so the fluid doesn't gravity feed into it:rockin:

Edit: in fact, I'm thinking a coiled tube alone, with a little sanitizer at the bottom of each coil, would be ideal. Yea that's the ticket a "multi airlock coil". Just stick it in, pour in some water, coil it up (all the while keeping it below the fermentor) so that a little water is in each coil, tape it to the wall, heck, you could even put a regular airlock on the end of that, but it would be unnecessary.

Nothing (open hole) would be better than sucking in airlock juice (unless you use vodka) Quit filling it!!!!!!

Or, . . . .that^

what is that?

ridnpowder said:

what is that?

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http://www.midwestsupplies.com/autoclavable-housing-sanitary-filter.html

http://www.midwestsupplies.com/sanitary-filter.html

Don't get it wet though.

I wonder if a 1" blowoff tube would fit over the top of an airlock, then you could dangle it over the side and make it work the way it was designed.

I had a similar dilemma when I recently cold crashed my first lager, a German Pils. I decided to go the solid bung route. I racked to secondary stuck the solid bung in and started dropping the beer to lager temps, but what was strange, I went in the next morning and my bung had shot out of the carboy and was laying on the bottom of my fridge. Here I was expecting the bung to get sucked in tighter not blown out? What up with that? I stuck it back in and checked after work and it was blown out again. The third time was the charm and it hasn't been blown out since.

Sir-Brews-Alot said:

I had a similar dilemma when I recently cold crashed my first lager, a German Pils. I decided to go the solid bung route. I racked to secondary stuck the solid bung in and started dropping the beer to lager temps, but what was strange, I went in the next morning and my bung had shot out of the carboy and was laying on the bottom of my fridge. Here I was expecting the bung to get sucked in tighter not blown out? What up with that? I stuck it back in and checked after work and it was blown out again. The third time was the charm and it hasn't been blown out since.

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yea thats cuz of temp differential I was talking about. If it was at 38F the whole time no suck in no push out.

"Suck tube" idea sounds like the best I've heard. I'ma try it.

butt... btw I was overfilling the airlock I think. It is no longer sucking in once it gets like 1/3 ofop

ridnpowder said:

Maybe its just me, but creating a vacuum with a solid bung on in a large glass carboy does not seem like a good idea. Especially if your cold crashing more than 3 deg. The beer should be fine in terms of risk of infection if its covered, and oxidation should be minimal (the change in volume isn't very large). The beer should reach the crash temp within a few hours where it will stop contracting and also stop pulling a vacuum. You can reapply the airlock at this point and let it sit for the desired crash time.

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3F differential makes a vaccume everytime I get it back down to 38F. Will that oxidize my beer? I've read stories on here about how a fermentor can even be open on the top and Co2 blanket protects it. In this case how does that work?

I think actually suck tube coil tube idea is best...actually now

CO2 is heavier than air so it "seeks" the lowest point, which would be on top of your beer in a fermentor, settling below the air.

Foil.

It may be true that CO2 is roughly 1.5x the density of air (wikipedia), but it does diffuse from high concentration to low concentration. Therefore the oxygen in the air (20%/V)will get to the beer. However, the change in volume do the temperature change is pretty small so there isn't much air & oxygen introduced into the carboy anyway.

boss429 said:

yea thats cuz of temp differential I was talking about. If it was at 38F the whole time no suck in no push out.

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Yeah, I guess I was just expecting it to "suck in," not "push out."
I would have just used an airlock if I thought it would be releasing pressure.

I'm still playing around with ideas...what is shown in the picture worked but is not the final set-up. The regulator was set at a ~.5 psi and the carboys have o-rings around the mouths to seal with the caps better. The next try will be blowing-off into a 3 gallon carboy with a carboy cap that then blows off into another container with starsan so the 3 gallon carboy is full of CO2 which will get sucked back into the crash cooled fermenter.

So I did a 10% red barleywine and a 7% pale from the same batch of 24# of malt- both were hooked up to blowoff tubes running into a quart or so of iodine solution.

After fermentation was complete I cold crashed. Normally at this point I replace the blowoff tubes with airlocks, but this time I didn't because I was getting hammered with a friend and well...

I came back today (a week later) and all of the iodine had either 1) been sucked up into the carboys or 2) evaporated - which I highly doubt.

Thoughts please. I'm worried about these.

^ Iodobeer, ewwy.

boss429 said:

3F differential makes a vaccume everytime I get it back down to 38F. Will that oxidize my beer? I've read stories on here about how a fermentor can even be open on the top and Co2 blanket protects it. In this case how does that work?

I think actually suck tube coil tube idea is best...actually now

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You are exposing your beer to oxygen so the risk is there. That co2 blanket is getting absorbed into your beer as the temp drops, and guess what that blanket is being replaced with when there is suckback? Oxygen! So let's say that there is oxygen in your headspace now and the fermenter is moved for racking. That few seconds of agitation and splashing will get that o2 into solution if it hasn't already been absorbed. Significant? Who knows? As l far as I know there haven't been any formal experiments or studies on coldcrashing and oxidation. It would be interesting to actually measure how much oxygen is getting sucked in so we can see if the risk is negligible or significant. All I know is that there is oxygen entering the fermenter during coldcrashing if there is suckback, and that makes enough sense to me to err on the safe side and only cold crash in a keg with co2 in the headspace. That said, if someone said that I am being too anal about it I probably wouldn't argue with them.

IL1kebeer said:

That co2 blanket is getting absorbed into your beer as the temp drops. . .

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:smack:

AnOldUR said:

:smack:

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?

More co2 goes into solution as the temperature of the beer drops. This should mean that the some of co2 in the headspace will be absorbed by the colder beer until an equilibrium is reached. This is why kegs are better carbonated cold and not at fermenting or room temps. Am I understanding this incorrectly?

Here's a quote from the link below:

"(3) Because solubility of CO2 decreases with increasing temperature, the partial pressure a given CO2 concentration has in liquid increases. So, CO2 from a beer escapes much faster when the beer is warm because of the increased partial pressure of CO2 due to the higher temperature. Inversely, with decreasing temperature, the partial pressure a given CO2 concentration has will decrease – allowing for increased gas concentrations or increased solubility."

http://www.draft-beer-made-easy.com/carbonation.html

The cold crash suckback has always bothered me and I've never accepted the recommendations not to worry about the air that comes back into the fermenter. It absolutely is an oxidation risk and as you've seen, the liquid in either airlocks or blowoff containers will get into the beer if you're not careful.

My current solution, that I haven't implemented or tested yet is to run the blowoff hose into a soft "cubetainer" in an air tight way. Also installed in that container is a silicone no-liquid airlock. As you're fermenting, CO2 fills the container to capacity and starts dumping through the flapper style airlock. When it's done, the container is full of CO2. Cold crash and in theory, the only thing that goes back into the fermenter is the CO2.

bobby_m said:

the cold crash suckback has always bothered me and i've never accepted the recommendations not to worry about the air that comes back into the fermenter. It absolutely is an oxidation risk and as you've seen, the liquid in either airlocks or blowoff containers will get into the beer if you're not careful.

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+1

IL1kebeer said:

?

More co2 goes into solution as the temperature of the beer drops. This should mean that the some of co2 in the headspace will be absorbed by the colder beer until an equilibrium is reached. This is why kegs are better carbonated cold and not at fermenting or room temps. Am I understanding this incorrectly? ]

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Sorry, that was a drunken post last night.

My interpolation is that there is no CO2 blanket. That gasses readily mix, so any O2 entering the fermenter will dilute the CO2 that’s present. My understanding is that CO2 absorbsion is a factor of temperature and pressure. Since the only pressure in your fermenter is atmospheric, whatever CO2 is present will not be forced into suspension just because there’s a temperature drop. At the point that you’ll be cold crashing there is already CO2 remaining in suspension. If what you suggest is true, an open bottle of beer in your refrigerator would never go flat or oxidize. A layer of CO2 coming out of suspension would blanket the surface and protect your beer. That’s never worked for me.

I have tried the silicone stoppers that Bobby mentioned, but my normal solution is to remove my carboy cap and immediately cover the top with foil and a tight rubber band. This is assuming that the only gas present in the carboy at that time is CO2 and that the quick process and small opening will minimize any exchange of gasses. In a situation of cold crashing a secondary, the small amount of surface area exposed combined with this technique helps me sleep at night.

But I could just be fooling myself.

Oh, and what you said about better to carbonate a keg cold. Not so sure about that either. If you set the pressure for the volumes of CO2 you're looking to get into your beer, I believe it will actually absorb faster at the higher temperature. Something about the speed that the molecules move around at. It’s just that it take less pressure to carbonate cold (not actually less CO2 though) and you won’t have to wait for your beer to chill before drinking.

Cold Crashing Primaries. . .

If you have the vertical space in your fridge, why not use one of these? I have never had suck back when using these, but always do when using a 3 piece.

Now it won't filter your air and it won't prevent oxygen from getting in when the liquid volume is decreasing. Kegs are a solution to the oxidation, but negate the very benefit of cold crashing. Not sure I would want to put any positive or negative pressure on a glass carboy.

AnOldUR said:

My interpolation is that there is no CO2 blanket. That gasses readily mix, so any O2 entering the fermenter will dilute the CO2 that’s present. My understanding is that CO2 absorbsion is a factor of temperature and pressure. Since the only pressure in your fermenter is at.

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I agree with that but it's such a huge myth that I didn't want to open that can of worms. I felt that it bad enough that I was already bad mouthing cold crashing. It would have been even more blasphemy if I went against the co2 blanket as well.

AnOldUR said:

Oh, and what you said about better to carbonate a keg cold. Not so sure about that either. If you set the pressure for the volumes of CO2 you're looking to get into your beer, I believe it will actually absorb faster at the higher temperature. Something about the speed that the molecules move around at. It’s just that it take less pressure to carbonate cold (not actually less CO2 though) and you won’t have to wait for your beer to chill before drinking

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Kinds getting off topic but you can carbonate a keg at any temperature you please. I believe that it's better cold since you use less co2.

solbes said:

Kegs are a solution to the oxidation, but negate the very benefit of cold crashing.

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Not entirely true. I know that it's more work but you can transfer to a fresh keg after the period of cold conditioning and leave all the crud behind. That's really unnecessary though since only the first pint or two will be cloudy. I just leave it in the initial keg and have really clear beer after cold conditioning without the risk of oxidation.

IL1kebeer said:

Kinds getting off topic but you can carbonate a keg at any temperature you please. I believe that it's better cold since you use less co2.

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It takes more pressure to get the same volume of CO2 into suspension in warm beer, but it's still the same amount of CO2. You don't use less because you forced it in cold.

IL1kebeer said:

That's really unnecessary though since only the first pint or two will be cloudy. I just leave it in the initial keg and have really clear beer after cold conditioning without the risk of oxidation.

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But if you don't transfer into a different serving vessle, it's not really cold crashing. So, what you're saying is that cold crashing is not necessary if you're kegging?

IL1kebeer said:

Not entirely true. I know that it's more work but you can transfer to a fresh keg after the period of cold conditioning and leave all the crud behind. That's really unnecessary though since only the first pint or two will be cloudy. I just leave it in the initial keg and have really clear beer after cold conditioning without the risk of oxidation.

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Mmm hmm, but the benefit of cold crashing is to avoid racking and drop most of the yeast in primary. If you rack to a keg used as a brite tank, you will still need to rack out of it to package. I have never used a keg as a brite tank for ales as I either cold crash or rack to a room temp carboy. Most of the yeast drops out in 24 hours when racked to room temp carboy.

Also agree with above on CO2 vs beer temp. Higher pressure is needed to carbonate warm beer, but it will still require the same amount of CO2.

AnOldUR said:

But if you don't transfer into a different serving vessle, it's not really cold crashing. So, what you're saying is that cold crashing is not necessary if you're kegging?

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In my experience, you will get the same result. After period of cold conditioning in a keg, all of the crud will drop to the bottom and your beer will be clear as day after the first pint or two. This also prevents sucking in oxygen while cold crashing in a carboy or bucket. Of course you still should be careful when you rack so you don't unnecessarily siphon a bunch of crud or dryhops or whatever, but again it should settle out anyway and you just might have a few more cloudy pints. If I'm going to fill a case with my beergun I cold condition for a week or two and then drink the first few pints. Everything after that is nice and clear and really to be bottled. In addition to myself believing that I have clear beer, I also haven't lost points in competition for appearance with this method, even with dryhopped beers.

A lot of other brewers skip cold crashing in the fermenter in favor of cold conditioning in the keg and report good results.

How about this....

Put a splash of starsan in a 2 liter soda bottle and fill the rest with CO2 via a carbonator cap, at 0-1 PSI. Then replace your airlock with a tube that's capped off with a ball lock disconnect. Lastly, attach that to the soda bottle and cold crash. The soda bottle will take the negative pressure and the only thing that will go back into the carboy is CO2.