Cold crashing versus just kegging

[TAK]

^That's why.

The kinetic theory of gas holds that - except under extreme (laboratory) conditions - the molecules are in constant, random, rapid motion.

Therefore, if you fill a vessel with one gas and introduce another, there will be a homogenous result in short order. No "wind" required...

Cheers!

+1, thanks.

 

[day_trippr]

Damn it. I hate you for teaching me this. I usually coldcrash in the carboy with a stopper completely blocking the air hole, and I currently have two batches on tap that I cold crashed for a week with an S-Shaped airlock. How long do you think I have before I'm going to have oxidation off flavors?

I honestly have no idea - or that there is a significant risk to begin with.

On this planet, in general conditions, oxidation is temperature-moderated.
So it's possible that the short, cold exposure to boundary-layer oxygen (as opposed to purposefully bubbling oxygen) of an undisturbed batch of beer would be so minor as to be dismissible.

Beyond that I have nothing to go on. And my thoughts about the whole thing go more to the "What if it was simple to just eliminate as an issue in the first place?" rather than "I think I can taste oxidation and really need to fix this!"

[edit] Otoh...the solubility of gas into a liquid is generally inversely proportional to temperature, so the take-up of whatever amount of oxygen introduced during cold-crashing could be expected to be higher than the same volume of oxygen above warmer beer. Which opens up the whole thing again...

Cheers!

 

[doodoobutter]

I have another question about the blanket. Why are we warned to be careful of c02 leaks putting out our pilots and causing gas build up when it just mixes with the air? Are they giving us these warnings based on myths? I would love to save up this discussion to pull that outta my ass when someone tries to give that warning haha, atodaso.

 

[GCPHomebrew]

I cold crash then keg. I find it reduces sediment in the keg.


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[GCPHomebrew]

It also carbs faster


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[grathan]

I ferment 2 weeks then keg. What sediment?

 

[SpeedYellow]

Crazy thought..........





I have the 3 piece bubbler. How bout filling a balloon with co2, and putting it over the bubbler. When the beer cold crashes, and sucks in thru the bubbler, it will be sucking in co2.





Am I crazy or might that just work?

That's actually quite genius. I'll totally consider that next time I crash cool, because it would certainly work.

 

[GCPHomebrew]

Primary 3 weeks Bry-97 66degrees. Icold crashed for a week. Added gelatin(yes Irish moss was in wort) for a week, secondaried 1day to room temp, dry hopped 4oz citra 3 days. There is 2 inches of trub/gelatin at the bottom of the Carboy. (Sorry for the reference to secondary clearing more). This will be my new technique for the next few brews to see if it's consistent. More trub in the secondary than was in the primary. FG 1.008. There is clear beer and there is "wow that's fricking clear beer"!!!! I will cold crash until tomorrow night and then keg. Kegging cold seems to increase carb rate and that means I can pull a beer sooner.. I'll update this week with photo of the clearness of the final thing.


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[Gameface]

I cold crashed my last couple brews because I wanted to see if it helped me get clearer beer but it really didn't. I always use wirfloc and even with the cold crashing my brews are always have chill haze at least. I just haven't had good luck with clarity yet. I can always tell when a keg has two pints left because the beer will finally be clear, and then it kicks.

Anyway lifting a 10 gallon primary into the kegerator is tough which is why I am asking how many do it.

Where do you ferment? I ferment in a chest freezer, so cold crashing is as easy as pressing a few buttons.

 

[doodoobutter]

Where do you ferment? I ferment in a chest freezer, so cold crashing is as easy as pressing a few buttons.

I cold crash in a chest freezer also, same freezer my kegs are in. It's 40F so not exactly the ideal 32F cold crash. I only have one freezer, so it's a common ground.

I said earlier, if I ferment at 60 to 70F for a few weeks, then secondary and cold crash, I always have crystal clear beer, always (with irish moss).

Not everyone agrees with the secondary, in fact, everyone is moving away from it. I find it easier and more consistent to secondary and put the secondary right into cold crash. You end up with like 1mm (estimated) on the bottom of the fermenter. It's just clear beer from there with little effort.

 

[djonesax]

Where do you ferment? I ferment in a chest freezer, so cold crashing is as easy as pressing a few buttons.

I ferment at basement temp which right now are about 68. I was thinking about either building a fermentation chamber or getting another chest freezer for fermentation and crashing but dont really want another appliance in my house. I think I may take a step back for now and try the swamp method for controlling the fermentation temp, and still use the kegerator to cold crash. Its the extra custom 6" collar on the freezer that makes it hard to place the 10 gallon fermenter inside but I can do it. Its lifting it out without splashing that's impossible. For that I am going to try to gas transfer from the 60L speidel.

Thanks,

David

 

[orangehero]

I honestly have no idea - or that there is a significant risk to begin with.

On this planet, in general conditions, oxidation is temperature-moderated.
So it's possible that the short, cold exposure to boundary-layer oxygen (as opposed to purposefully bubbling oxygen) of an undisturbed batch of beer would be so minor as to be dismissible.

Beyond that I have nothing to go on. And my thoughts about the whole thing go more to the "What if it was simple to just eliminate as an issue in the first place?" rather than "I think I can taste oxidation and really need to fix this!"

[edit] Otoh...the solubility of gas into a liquid is generally inversely proportional to temperature, so the take-up of whatever amount of oxygen introduced during cold-crashing could be expected to be higher than the same volume of oxygen above warmer beer. Which opens up the whole thing again...

Cheers!

In the new BYO this exact question is addressed and Ahston Lewis (aka Mr. Wizard) writes that non actively fermenting yeast also absorbs oxygen and provides a measure of protection from oxidation (also why bottle conditioned beers have longer shelf-lives). He also mentions that there is risk of contamination with the suck-back and suggests using some sort of filter such a cotton plug.

 

[day_trippr]

My plan goes into action tomorrow.

I totally expect plenty of rocks thrown in my general vicinity...

Cheers! (stay tuned! )

 

[day_trippr]

Aaaaand here we go! Best as I can tell, the first CO2-powered cold-crash on HBT!

About a week ago I set one of my CO2 regs for just a hair above the lower stop - not even to the "zero" hash mark on the gauge - and left it like that, checking daily to see if it drifted. After a few days it got up to an indicated .5 psi and I dialed it back down to the original "below zero" mark where it stayed through to this afternoon.

The two carboy caps already had the gas posts for doing CO2 pushes between vessels, so all I needed to do was come up with a gas-tight connection to the balloons. A short piece of tubing kept the cap nipple from collapsing, a piece of blue tape around the balloon kept the worm clamp from tearing through...and the rest is history.

There's so little pressure involved that the balloons just stand there at attention but won't expand. I think they might be effective fuses should things go awry but I'm not inclined to prove it

Cheers!

 

[grathan]

Be neat to put a balloon on while its still fermenting.

 

[AnOldUR]

Replace your airlock with one of these during the last days of active fermentation (after there's no chance of blow-off) and no O2 can enter during cold crashing.

Fits 3,5,6 & 6.5 Gallon carboys and 500ml flasks. A breathable Silicone stopper that acts as both a stopper and an airlock. Unique design allows CO2 pressure to escape but keeps Oxygen and airborne contamination out.

 

[day_trippr]

Replace your airlock with one of these during the last days of active fermentation (after there's no chance of blow-off) and no O2 can enter during cold crashing.

I don't think you can pair "breathable" with "no O2 can enter"...

Cheers!

 

[AnOldUR]

I don't think you can pair "breathable" with "no O2 can enter"...

The check valve breathes out, but not in.

"Everybody knows that . . ." :cross:

 

[SpeedYellow]

Aaaaand here we go!...

Whoooa, methinks you made this way too complicated. Why not simply blow up a balloon with co2 (either from the tank or during fermentation), then stick the balloon onto the carboy right when you start cold crashng? Then remove in the morning when done, or just leave it.

 

[day_trippr]

Whoooa, methinks you made this way too complicated. Why not simply blow up a balloon with co2 (either from the tank or during fermentation), then stick the balloon onto the carboy right when you start cold crashng? Then remove in the morning when done, or just leave it.

"Incoming! Hit the dirt!!"

Complicated? Au contraire. This was actually the easiest way for me.

Both of my beer fridges are outfitted with CO2 drops for carbing kegs, fed by a dual-body regulator. And I already had the carboy caps rigged with the CO2 posts for pushing beer. All I needed was a way to plug the second hole in the carboy caps, which I was going to do with plastic dowels, but then it dawned on me the balloons would not only do that but provide visible indicators of what was going on - not to mention adding a degree of plasticity to the gas model at work.

The idea of filling balloons with CO2 and somehow attaching them to the fermenters has been proposed ad infinitum, but to do it neatly/sans waste from failed attempts, a valve would be in order. Then you just need a way to connect the other side of that valve to the fermenter and you're in bidness.

This was easier than that as I already had everything in place or on hand but the balloons.

Anyway...

In the wee hours of the morning before I hit the rack the beer had dropped from 68F to 42°F on the way to 34°F. I shut off the gas and when I checked upon awakening this morning the beer was at 36°F and the balloons were flat, so I turned on the gas again.

So things are progressing nicely, the hop pellet mush hit the bottom hard and is being pancaked by all the other little bits o' stuff dropping out. I'll be kegging these Sunday with a CO2 push before the Pats thrash the Raiders...

Cheers!

 

[day_trippr]

The check valve breathes out, but not in.

"Everybody knows that . . ." :cross:

So, you think that plug will maintain the rather significant vacuum that will result when crash-cooling - but without risking an implosion?

Interesting...

Cheers!

 

[grathan]

Replace your airlock with one of these during the last days of active fermentation (after there's no chance of blow-off) and no O2 can enter during cold crashing.

I have observed the affects of 20# of vacuum over time. I highly doubt this works.

 

[The_Bishop]

I cover the carboy opening with sanitized foil before I cold crash for 24 hours. Gelatin fining goes in, then another 24 hours. Then I keg. Beer is very, very clear going into the keg. Carbonation happens faster because it's already cold, I don't introduce a heat load (warm keg) into my keezer, and it makes me happier that way.

 

[AnOldUR]

I have observed the affects of 20# of vacuum over time. I highly doubt this works.

I haven't used one of the silicone caps for cold crashing, but have sealed carboys other ways and never had a problem. I'm sure there are formulas, but I can't seem to find the one I'm looking for. Where are you coming up with a 20PSI change from dropping temperature 35 degrees? All I could find was a volume calculator that says the volume will go from 5 gallons to 4.96 gallons with a temperature drop from 70 to 35 degrees, so about a 5 ounce loss. Doesn't seem like enough for a 20PSI drop, but I don't know.

It does seem like if sealed glass carboys were used for many years to transport water, that a 35 degree temperature differential between filling at the source and conditions during shipping would be that unusual.

 

[day_trippr]

[...]
It does seem like if sealed glass carboys were used for many years to transport water, that a 35 degree temperature differential between filling at the source and conditions during shipping would be that unusual.

As it wouldn't make sense to transport partially filled vessels you can bet they were filled to the top.

The issue here is the head space pressure dropping, perhaps enough to collapse the vessel...

Cheers!

 

[grathan]

I haven't used one of the silicone caps for cold crashing, but have sealed carboys other ways and never had a problem. I'm sure there are formulas, but I can't seem to find the one I'm looking for. Where are you coming up with a 20PSI change from dropping temperature 35 degrees? All I could find was a volume calculator that says the volume will go from 5 gallons to 4.96 gallons with a temperature drop from 70 to 35 degrees, so about a 5 ounce loss. Doesn't seem like enough for a 20PSI drop, but I don't know.

It does seem like if sealed glass carboys were used for many years to transport water, that a 35 degree temperature differential between filling at the source and conditions during shipping would be that unusual.

20" is an estimate after watching my plastic fermeter collapse in on itself.

 

[orangehero]

20 psi vacuum ≠ 20" Hg vacuum

I doubt the carboy will implode. If my caculations are correct, then assuming you have 5 gal of beer and 1 gal of headspace at 70°F and cool the beer down to 34°F, then you should see approximately 3" Hg of vacuum (or 1.5 psi vacuum). I'm not an engineer and could be wrong though, the different measurements for vacuum are a little tricky.

 

[grathan]

This was a speidel tank with 4 gallons of headspace. About 80* to 33*. I wonder what you would calculate there?

I bet with the silicone stopper design more vacuum would be better than less anyways.

 

[AlDogWV]

So, question to all of those worrying about oxygen and CO2 blankets being nonexistent: have you ever had a serious issue with oxidation as a result of conventional cold crashing??

I leave the airlock right in the primary fermenting bucket OR glass carboy (whichever vessel happened to be handy when I first put the wort into a fermenter) and drop it down into my chest freezer for a few days. I then syphon the crashed beer into the keg.

I've done it this way at least a hundred times and have never had any hints of oxidation or off flavors.

The whole balloon get-up seems very excessive to me. Have fun with your experiments and all, but I don't have time to worry about things that really are of no worry.

 

[AnOldUR]

The issue here is the head space pressure dropping, perhaps enough to collapse the vessel...

The issue is the contracting of both liquids and gasses at cooler temperatures creating a vacuum.

Finally found out that it's the Ideal Gas Law we're dealing with and a calculator that I could figure out how to use. :cross:

I'm coming up with a 1 psi drop in pressure in about 1.5 gallons of head space with a 35 degree drop in temperature. Close to the same number as orangehero got.

Bottom line. No, you won't implode your glass carboy, and no, you won't suck the silicone stopper into the carboy. You will suck a very small percentage O2 into the head space when you remove the stopper, but absorbsion is a matter of exposure time. Just transfer right after removing the stopper and you're good.

Like I said. I've never used the silicone stopper for cold crashing, but thought it might work well if put on after removing a blow-off tube. Personally, I've simply been switching to a carboy cap with caps on both openings when I cold crash.

 

[hunter_le five]

have you ever had a serious issue with oxidation as a result of conventional cold crashing??

.....

I've done it this way at least a hundred times and have never had any hints of oxidation or off flavors.

No and ditto.

I cold crash and have never taken any measures to prevent oxygen from getting sucked into the primary. I've yet to taste anything that tastes like oxidation as a result.

Granted, I'm not doing any sort of aging and tend to finish my kegs while they're still *relatively* young. Maybe in the long-term some sort of oxidation would occur, but I have experienced no adverse effects, so I won't worry about it.

 

[grathan]

I ruined 2 of my most expensive batches a year ago due to cold crash. The head space was 4 gallons and the time was a week at 34*. That is a fairly large head space and the time spent cold crashing is a bit excessive, but undrinkable none-the-less.

 

[Gameface]

This was a speidel tank with 4 gallons of headspace. About 80* to 33*. I wonder what you would calculate there?

I bet with the silicone stopper design more vacuum would be better than less anyways.

I use speidel fermentors, the 60L ones and I typically have 10.5G of beer in them (so a good 5G worth of head space). I purchased additional pour valves that I use on the top bung to connect to my blow off tube (see pic). When I cold crash I close that valve and I've never had the fermenter collapse.

I'd like to know more about what happened with yours.

 

[orangehero]

This was a speidel tank with 4 gallons of headspace. About 80* to 33*. I wonder what you would calculate there?

I bet with the silicone stopper design more vacuum would be better than less anyways.

2.3" Hg vacuum or 1.1 psi vacuum.

I ruined 2 of my most expensive batches a year ago due to cold crash. The head space was 4 gallons and the time was a week at 34*. That is a fairly large head space and the time spent cold crashing is a bit excessive, but undrinkable none-the-less.

The headspace is not what determines how much suckback you have, rather it's mostly the volume of beer.

How long do you typically cold crash? Without finings I've never seen beer to clear to any significant degree until at least a week.

 

[brew_ny]

I ruined 2 of my most expensive batches a year ago due to cold crash. The head space was 4 gallons and the time was a week at 34*. That is a fairly large head space and the time spent cold crashing is a bit excessive, but undrinkable none-the-less.

I cold crash 11.5 gallon batches in a 13 gallon fermenter just dumping the water out of a three piece airlock, and cold crash for 48 hour after it hits 34 F

and never had a problem

but as you say 4 gallon head space and a week may be a bit much

but didn't you say before you dump 50 % of your batches?

S_M

 

[grathan]

Jeeesh I wish I took a picture. It's a different tank than yours. The top is smaller, maybe 8" across? I think its 8 gallons. I am not sure. It could be the physics of the tank design or it could also be that your valve leaked under vacuum (highly likely unless there was a massive rush when you cracked it).

The beers that were ruined were massively dry hopped beers. 8 oz+ dry hop. If you've ever done 2+oz/gal before you already know oxidation can be an issue.


I disagree with the statement about it being the volume of beer and not the headspace that creates suckback. The air condensates which causes the vacuum, sure the liquid may shrink a little, but its nothing compared to the air. When I cold crash a full carboy there is very little suckback.

 

[orangehero]

I disagree with the statement about it being the volume of beer and not the headspace that creates suckback. The air condensates which causes the vacuum, sure the liquid may shrink a little, but its nothing compared to the air. When I cold crash a full carboy there is very little suckback.

Although the air plays a part the liquid shrinkage should have a more significant effect.

For example:

If you have a 25 L vessel filled with 20 L of beer and chill from 20°C to 1°C, you will create ~2.4" Hg vacuum.

If you have a 25 L vessel filled with 5 L of beer and chill from 20°C to 1°C, you will create ~2.1" Hg vacuum.

 

[grathan]

Just as if you were to boil in your kettle with the top sealed it would explode, and equal an opposite reaction occurs when the gas is cooled. This is Charles Law.

If you were to leave a scuba diving tank in the sun. It would increase 9psi for every degree Celsius temperature increase. Much more significant than the liquid numbers.

 

[j1n]

I ferment in a chest freezer and at the end of fermentation when im going to cold crash, the chest freezer is mostly filled with co2 since its been closed most of the time and all the co2 produced from the beer is in there. So when i cold crash there is prob some o2 in there but id say 90% is co2. as soon as you stick your head in a little and sniff all you get is that sharp co2 up your nose.

 

[orangehero]

Just as if you were to boil in your kettle with the top sealed it would explode, and equal an opposite reaction occurs when the gas is cooled. This is Charles Law.

That doesn't refute my statements. You're welcome to calculate it for yourself.

If you were to leave a scuba diving tank in the sun. It would increase 9psi for every degree Celsius temperature increase. Much more significant than the liquid numbers.

Heating a closed scuba tank at atmospheric pressure 1°C will not generate 9 psi. Our carboys aren't pressurized to 3000 psi, which I'm assuming are the conditions you are referring to.