So I ran into a lot of issue cold crashing my carboy in my fridge with really hopped IPAs and oxidation problems. I wonder would taping the gap where the bung and carboy meet and putting tape over the airlock cover help reduce introduction of oxygen? Just spit balling here. Any thoughts.
Suck back during cold crashing and a poss remedy?
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No, at some point you need to open it and the air will rush in. I guess if you go straight to transferring it time exposure to the O2 will be minimal. You'd have to seal up really good as I suspect there'll be quite a vacuum generated.
olotti
Well-Known Member
So u don't think o2 absorption will be less by taping it. This is after dry hopping so for instance I'm about to bottle this batch tomm I was gonna do this taping thing and cold crash for like 12 hrs then only time I open it is to transfer to bottling bucket.
Easycreeper
Well-Known Member
If he were to cold crash and create a vacuum, he could bring it back to starting temp afterwards and negate the vacuum. Going slightly over the starting temp would lightly pressurize the carboy, forcing air out instead of bringing it in.
All of this assumes an airtight seal can be achieved.
dwhite60
Well-Known Member
The less airspace in your secondary the less "suck back" you'll get. The smaller volume of air will contract less volumetrically as it cools.
Think of the difference between a cubic foot of air contracting ten percent versus a cubic inch of air contracting ten percent.
All the best,
D. White
Think of the difference between a cubic foot of air contracting ten percent versus a cubic inch of air contracting ten percent.
All the best,
D. White
I believe switching to a S-Bubbler would solve the problem.
Possible remedy? Just don't cold crash.
Pretty much this.
Try using whirlfloc or moss in your boil. Works for most stuff.
I do cold crash on occasion. I saw some people rigged up a way to put a balloon full of co2 on an orange cap on the carboy. I tried that, but it was a bit of a pain...
I simplified it by using the big punching balloons and just zip it to the top of the carboy. It's big enough to stretch over the neck. Works great, but you have to have enough room in your fridge to accommodate it. I don't have a pic, or I'd post it. I'll remember to take one next time.
olotti
Well-Known Member
Pretty much this.
Try using whirlfloc or moss in your boil. Works for most stuff.
I do cold crash on occasion. I saw some people rigged up a way to put a balloon full of co2 on an orange cap on the carboy. I tried that, but it was a bit of a pain...
I simplified it by using the big punching balloons and just zip it to the top of the carboy. It's big enough to stretch over the neck. Works great, but you have to have enough room in your fridge to accommodate it. I don't have a pic, or I'd post it. I'll remember to take one next time.
I use whirlfloc on every beer but I use a lot of Conan and 1318 and I've tried not cold crashing at all and it just leaves way to much yeast in suspension. Even two weeks after bottling the yeast in suspension is still very present so I like to cold crash for 12. Hrs max to just clear even a little bit of that yeast out.
Does cold crash/suck back really bring in enough O2 to cause oxidation in a 5-gallon batch? I really don't know the answer, but I'd definitely look to other possible sources of oxidation before blaming the suckback.
It does. I use 4' long 1 1/4" OD blowoff tubes on my carboys, run into a bucket of starsan. I tried cold crashing like that once, thinking the co2 in the tube should be more than enough to keep from sucking in air. I was wrong. Really wrong. I woke up the next morning, and almost the entire 1 1/2 gallon bucket had been sucked into the carboy. That was only about a 20° swing too. I ended up dumping the batch. Didn't want to play around with it. Yuk.
That's a pretty decent vacuum to suck a gallon of starsan 2 1/2' high through a 1 1/4" OD tube. I'd bet that would be quite a bit of oxygen if it was just air.
It does. I use 4' long 1 1/4" OD blowoff tubes on my carboys, run into a bucket of starsan. I tried cold crashing like that once, thinking the co2 in the tube should be more than enough to keep from sucking in air. I was wrong. Really wrong. I woke up the next morning, and almost the entire 1 1/2 gallon bucket had been sucked into the carboy. That was only about a 20° swing too. I ended up dumping the batch. Didn't want to play around with it. Yuk.
That's a pretty decent vacuum to suck a gallon of starsan 2 1/2' high through a 1 1/4" OD tube. I'd bet that would be quite a bit of oxygen if it was just air.
Huh. Good point - makes perfect sense.
Not sure if this is an option, but maybe a pressurized transfer into a CO2-filled keg, then cold crash in the keg with the gas connected?
Anybody remember PV=nrt? Fropping the temp from 65 to 32 (291 to 273 in kelvin) means you drop the volume og gas by (291-273)/291 = 7%. IF you just have gas moving, you'll draw in about 7% of the volume of your headspace in normal air. (not the same as accidentally starting a siphon.)
You'll introduce way more oxygen opening the fermenter to dry hop than you suck back from cold crashing. If you want to minimize O2, you'll be better off just dry hopping when there is a little yeast activity still going so the CO2 can drive out the unwanted O2.
You'll introduce way more oxygen opening the fermenter to dry hop than you suck back from cold crashing. If you want to minimize O2, you'll be better off just dry hopping when there is a little yeast activity still going so the CO2 can drive out the unwanted O2.
Rush
Well-Known Member
An S-bubbler will prevent liquid intake (starsan/vodka/whatever is in your airlock), but it will just function in reverse. Reverse function means that it will still allow oxygen to enter through suck-back from the temperature transfer.
Steveruch
Well-Known Member
I would also. I may be wrong, but I'm pretty sure that water expands as it chills, which is why ice floats, so I'm not understanding why there would be any suckback since beer is mostly water,
Water expands when it freezes, but as it chills it it shrinks. For instance your wort shrinks in volume about 4% going from a boil to pitching temps.
Here we go again...
Don't want to disappoint you @k1ngl1ves , so yet again:
The CO2 blanket is a myth. Gases of different molecular weights do not stratify, in fact they do the opposite and homogenize by diffusion. Look at the video below. Br2 is about 3.6 times heavier than CO2, yet it completely inter-diffuses with air in about 30 minutes. CO2 inter-diffuses even faster, like the NO2 shown later in the video (NO2 and CO2 are about the same weight.)
[ame]https://www.youtube.com/watch?v=_oLPBnhOCjM[/ame]
Brew on
To the OP. The way to eliminate suck back during cold crashing is to:
Brew on
- Rack to a CO2 purged keg with about 15 - 25% of fermentation yet to go. For best results use a CO2 pressure transfer from the primary to the keg.
- Finsh the fermentation in the keg with a spunding valve (set to about 3 - 5 psi.)
- Cold crash in the secondary keg.
- CO2 pressure transfer to CO2 purged serving keg when fermentation is complete.
Brew on
Wouldn't air (O2) get sucked back in even though the liquid would not?
The_Bishop
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This is how I solved the suckback/O2 issue when cold crashing:
It's a 2 gallon ziplock, filled with CO2. I have it attached to my conical via a gas connector, but you can duplicate the same thing with some tubing stuffed into a bung. To get the tubing into the ziplock, cut a corner on the diagonal so it's somewhat smaller than the tubing, and push the tubing through from the inside. Seal the joint with a few wraps of high quality electrical tape.
On a carboy, a 1 gallon ziplock bag is sufficient.
Now you can cold crash and keep the O2 out of your fermenter.
It's a 2 gallon ziplock, filled with CO2. I have it attached to my conical via a gas connector, but you can duplicate the same thing with some tubing stuffed into a bung. To get the tubing into the ziplock, cut a corner on the diagonal so it's somewhat smaller than the tubing, and push the tubing through from the inside. Seal the joint with a few wraps of high quality electrical tape.
On a carboy, a 1 gallon ziplock bag is sufficient.
Now you can cold crash and keep the O2 out of your fermenter.
MidAtlanticBrew
Well-Known Member
Unfortunately it's much more then the real gas law predicts. As the beer cool, gas is more soluable in the beer so it dissolves from the head space into the beer, continuing the vacuum. This probably explains K1ingl1ves 1.5 gallon suck back he mentioned in this thread. Best bet for cold crash is make-up C02 via balloon or better yet low pressure co2 from your regulator. Sealing, then releasing the seal before packaging in a keg, in a safe way, is probably not too bad as long as you run a keg purge at the end. Cold crashing without a seal or make-up Co2 might make for huge oxidation problems.
Eventually, sure. In this timeframe, no way. Even if a pressurized situation, it takes a week+ to reach equilibrium. eg a keg hooked up to CO2. With only atmospheric pressure, gas enters liquids very slowly unless you are doing something to break that surface tension. eg shaking a keg vs set it and forget it.
There are lots and lots of homebrewers cold crashing without a fancy setup and having no issues with o2. If the OP is having consistent issues with O2, then O2 is entering some other way in the process.
Steveruch
Well-Known Member
I did not know that.
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