Cold Crashing and Oxygen

[kenmcchord]

While I'm waiting on the latest version of the Cold Crash Guardian from Bobby...today I've improvised what I hope to be a good solution to avoid the O2 invasion.

I filled the blue top keg with starsan, emptied that into another keg with forced CO2, then hooked up the tube pictured above with a fluid ball lock to a sanitized hose that would fit the blow off fitting. I purged the line as best I could with CO2 then made the above connection, and added an open gas ball lock to the gas post. I'm figuring that CO2 is heavier than regular air so the CO2 ought to stay low in the keg, and pulling any gas from the fluid post should get the gas that is lowest in the keg.

I'm hoping this is better than just leaving the fitting wide open, and I really wanted to cold crash since I have the glycol chiller. I mean, really this can't be any worse than leaving it wide open, right?

Comments?

 

[marc1]

While I'm waiting on the latest version of the Cold Crash Guardian from Bobby...today I've improvised what I hope to be a good solution to avoid the O2 invasion.

View attachment 704362

I filled the blue top keg with starsan, emptied that into another keg with forced CO2, then hooked up the tube pictured above with a fluid ball lock to a sanitized hose that would fit the blow off fitting. I purged the line as best I could with CO2 then made the above connection, and added an open gas ball lock to the gas post. I'm figuring that CO2 is heavier than regular air so the CO2 ought to stay low in the keg, and pulling any gas from the fluid post should get the gas that is lowest in the keg.

I'm hoping this is better than just leaving the fitting wide open, and I really wanted to cold crash since I have the glycol chiller. I mean, really this can't be any worse than leaving it wide open, right?

Comments?

The gasses will mix readily. Popping a spunding valve onto that keg set to low pressure will prevent any O2 coming back in.

 

[kenmcchord]

The gasses will mix readily. Popping a spunding valve onto that keg set to low pressure will prevent any O2 coming back in.

I don't know what a spunding valve does. I guess I need to research that. I've probably already had significant O2 contact at this point if the gasses mix that readily. Probably try to keg it in the morning then, live with what I've got.

 

[marc1]

I don't know what a spunding valve does. I guess I need to research that. I've probably already had significant O2 contact at this point if the gasses mix that readily. Probably try to keg it in the morning then, live with what I've got.

A spunding valve is a one way valve that releases at a set pressure. So you set the pressure to a few PSI and whenever the CO2 builds over that, it will release it. I've had a couple, the Kegland one performs much better than the other brass one. If your fermenter is capable of holding pressure, when there's a few points of fermentation left to go, you can raise the release pressure and get most of your carbing done without your CO2 tank.

 

[Jim R]

Why don't you just do a pressure transfer to the keg at the end of fermentation and then cold crash in the sealed keg.

I use the same SS Brewtech fermenter. I usually let my beer ferment for 2 weeks in the fermenter in my temperature controlled refrigerator (usually with the temperature in the mid 60's). Then I basically take my blow off tube and hook it up to my CO2 tank to apply 1-2 psi of CO2 pressure to the fermenter to do a pressure transfer to my keg. I put the fermenter on the countertop and the keg on the floor to get the benefit of gravity also. Before the transfer I fill the keg with Star San and purge it with CO2. Then after the pressure transfer I simply cold crash the sealed keg with no concern for oxygen exposure or suck-back into the fermenter. Of course, I carbonate in the keg at the same time as I am cold crashing.

 

[jddevinn]

If that's all you have instead of putting the open gas in line put CO2 into the keg at some low pressure and then disconnect the tank. When the flow slows down add some more CO2 and repeat using the keg as a buffer.

 

[Baglorious]

I have used a fairly simple solution, depending on my fermenter type. I use a ball lock gas post and gas post connector with tube as my blowoff. When fermentation is over and I cold crash, when negative pressure develops, the fermenter "scrunches" (shrinks)... and I simply add some CO2 in from the tank. IIt couldn't be easier, as you can see when the fermenter is 'unscrunched' and back to normal size. Most fermenters, with a little tweaking, can hold negative pressure.

Here are some pic of my highly engineered rig for the couple of Big Mouth Bubblers that I own. Just a simple carbonation cap and a self-drilled stopper. (I added a stainless washer just to form a better 'flange'... but that isn't really necessary.) It is obvious that this works well, and it is not allowing air to leak inward, by the amount of visible "scrunch" I can see that holds and does not diminish. (I just finished a batch 2 days ago... and wish I had taken pics.) As an added bonus, the cap/stopper allows me to push from the fermenter for keg filling. (I still elevate the fermenter to transfer... but can slowly add CO2 to keep all oxygen out during transfer. Again, you can see the fermenter flex inward and 'scrunch' during the drain... then add a bit more CO2 to restore the fermenter to full size, and repeat as you drain to keg.)

This could be adapted to any plastic fermenter... as I bet they all can 'scrunch'. (My Better Bottles sure could... they'd scrunch fully when I had a 3 piece airlock in and cold crashed, and I'd watch them "pop" back to shape when I pulled the airlock before I knew anything about the O2 being an issue.)

I bet you could use a stopper and adapt the same idea to an SS brew bucket... as I bet they'd hold negative pressure. (I'd probably add a weight set atop the lid to ensure the gasket could do its job.)

I now mainly use "kegmenter" type 15.5 gal fermenters (SABCO) which make this easy. Using parts from Bobby, I added a spunding valve setup to use for my blowoff. (I don't actually "spund.") That fermenter can obviously hold negative pressure... so I just let it crash, then add the CO2 in when I push to kegs. Essentially, I use the same process with fancier equipment.

 

[kenmcchord]

Well from the sound of your comments I probably got some contact with air in the 12 hours I cold crashed. This morning I went out and disconnected that keg, then reinstalled the blow off tube into a jar of starsan. The beer has been at 35° for the past 12 hours, I've got to think it's contracted all it's going to contract and whatever contact I've got is going to be it.

I get the comment of using the spunding valve, but isn't that a valve that protects over pressure situations? In the case of the cold crash it's the vacuum that's the issue here. I'm figuring I've already created whatever damage I've got, and with the tube in the starsan I have somewhere for any gas that comes from any further yeast activity. Like I said, I have the cold crash guardian in the mail, but that wouldn't probably have helped me in this fermentation. I'm hoping I won't notice any problems, may not be the best beer ever brewed, but I'm learning.

Thanks to everyone that replied, I truly appreciate the tips.

 

[kenmcchord]

Why don't you just do a pressure transfer to the keg at the end of fermentation and then cold crash in the sealed keg.

I use the same SS Brewtech fermenter. I usually let my beer ferment for 2 weeks in the fermenter in my temperature controlled refrigerator (usually with the temperature in the mid 60's). Then I basically take my blow off tube and hook it up to my CO2 tank to apply 1-2 psi of CO2 pressure to the fermenter to do a pressure transfer to my keg. I put the fermenter on the countertop and the keg on the floor to get the benefit of gravity also. Before the transfer I fill the keg with Star San and purge it with CO2. Then after the pressure transfer I simply cold crash the sealed keg with no concern for oxygen exposure or suck-back into the fermenter. Of course, I carbonate in the keg at the same time as I am cold crashing.

Like I said in my first comment it's that I got this glycol chiller and wanted to see how well it cold crashed. In hind sight I wish I had done exactly what you've said here, but next batch I'll have the guardian to protect from O2 contact.

 

[kenmcchord]

A spunding valve is a one way valve that releases at a set pressure. So you set the pressure to a few PSI and whenever the CO2 builds over that, it will release it. I've had a couple, the Kegland one performs much better than the other brass one. If your fermenter is capable of holding pressure, when there's a few points of fermentation left to go, you can raise the release pressure and get most of your carbing done without your CO2 tank.

I'm not exactly sure how much pressure these SSbrewtech buckets can take, so I'd be uncomfortable allowing pressure to build in them. That said I'm eyeing a better fermenter for the future, one that can do much of what you're talking about. Thanks for the explanation of the spunding valve!

 

[kenmcchord]

Holy crap, what a disaster cold crashing became!

I brew in my garage in central Florida where it was 90° and humid today. I have a/c in the garage (4 ton rheem central air handler, works quite well) but when I'm out of the garage I keep in 80°-81°. So once I cold crashed to 36° the moisture coming off the fermenter was pretty staggering, the neoprene insulation cover was soaking wet and there was virtually a puddle under the fermenter. Additionally, after replacing the keg filled with CO2 with the starsan jug and blow off tube, the cycling of the chiller keep making the starsan creep up into the fermenter.

I decided to just keg the beer tonight, so it's in the kegerator now carbing up. Man, I learned a few good lessons with this attempt to cold crash, I'm hoping the Cold Crash guardian will have enough volume of air to allow me to cold crash for a few days. All in all, this batch was a good learning opportunity. I'll do better next time!

 

[Jim R]

That SS Brewtech cooling system seems like an overly complicated and expensive fermentation cooling system especially with a glycol chiller. I found a $180 mini refrigerator at Home Depot that fits that fermenter and works perfect for cooling with a $30 Inkbird temperature controller. It would also work for cold crashing with that Cold Crash Guardian but for someone that kegs anyway it is easier to just cold crash in the sealed keg.

 

[kenmcchord]

That SS Brewtech cooling system seems like an overly complicated and expensive fermentation cooling system especially with a glycol chiller. I found a $180 mini refrigerator at Home Depot that fits that fermenter and works perfect for cooling with a $30 Inkbird temperature controller. It would also work for cold crashing with that Cold Crash Guardian but for someone that kegs anyway it is easier to just cold crash in the sealed keg.

The reason I wanted to glycol chiller was so I could ferment more than one batch at a time, and at different fermentation temperatures. I agree with the cold crash re: kegging, however I was thinking that a cold crash before kegging would eliminate some of the material that would otherwise make it into the keg. Really I'm experimenting with it all right now, I suspect that I have a system that works well for me soon enough. To be clear, I am getting back into brewing after having a few years away and I now have the space and time to play around with a bigger set up.

What is for sure is that without a way of controlling the suck back (as in the cold crash guardian or similar device) cold crashing can be a disaster. I won't attempt that again without some protection.

 

[VikeMan]

I agree with the cold crash re: kegging, however I was thinking that a cold crash before kegging would eliminate some of the material that would otherwise make it into the keg.

You were thinking correctly.

 

[Dland]

If one cold crashes in kegs, after spunding, there is no O2 introduction, and no extra CO2 needed.

Yes, there might be a bit more yeast sediment at bottom of keg. 3/4 inch off dip tubes solves that. Perhaps another case of many ways to make beer, and different preferences of simplicity over love of gadgets and process.

 

[jddevinn]

If one cold crashes in kegs, after spunding, there is no O2 introduction, and no extra CO2 needed.

Yes, there might be a bit more yeast sediment at bottom of keg. 3/4 inch off dip tubes solves that. Perhaps another case of many ways to make beer, and different preferences of simplicity over love of gadgets and process.

I just hate that when I get sediment into the keg that it can be pouring perfectly clear, but then if I pull the keg and move it all the sediment gets stirred up again.

 

[EDF713]

Another option besides cutting the diptube is a floating dip tube, I have a couple of these - Top Draw® Beer Pick Up Tube. This is strongly recommended if you spund or cold crash in the keg. I added a stainless steel nut on the end of the tube with the float since it would sometimes pull air.

 

[Dland]

I just hate that when I get sediment into the keg that it can be pouring perfectly clear, but then if I pull the keg and move it all the sediment gets stirred up again.

There is another case of different preferences for different brewers, w my 12 keg brew freezer/fridge, my kegs remain stationary form crash to kick.

 

[jddevinn]

There is another case of different preferences for different brewers, w my 12 keg brew freezer/fridge, my kegs remain stationary form crash to kick.

Most of the time my kegs stay in the bar at home, however, I've made a portable bar and a couple times a year take kegs to events/parties (well not this year).

 

[eric19312]

Holy crap, what a disaster cold crashing became!

I brew in my garage in central Florida where it was 90° and humid today. I have a/c in the garage (4 ton rheem central air handler, works quite well) but when I'm out of the garage I keep in 80°-81°. So once I cold crashed to 36° the moisture coming off the fermenter was pretty staggering, the neoprene insulation cover was soaking wet and there was virtually a puddle under the fermenter. Additionally, after replacing the keg filled with CO2 with the starsan jug and blow off tube, the cycling of the chiller keep making the starsan creep up into the fermenter.

I decided to just keg the beer tonight, so it's in the kegerator now carbing up. Man, I learned a few good lessons with this attempt to cold crash, I'm hoping the Cold Crash guardian will have enough volume of air to allow me to cold crash for a few days. All in all, this batch was a good learning opportunity. I'll do better next time!

How about running a dehumidifier in the garage?

 

[Jim R]

I just hate that when I get sediment into the keg that it can be pouring perfectly clear, but then if I pull the keg and move it all the sediment gets stirred up again.

I get very little sediment in my kegs when I cold crash although I usually leave the beer in the fermenter for 2 weeks before I transfer to the keg for cold crashing. As long as I don't rush fermentation, I don't need a floating dip tube, a cut off dip tube and don't even get sediment in the first glass.

 

[kenmcchord]

How about running a dehumidifier in the garage?

Not a bad idea, but the garage is rather large (1800 sq ft) and I'd have to see what size I'd need. Good chance that would be an unworkable solution given the size of the space. The moisture wasn't a problem until I cold crashed so I might have to bail on the cold crashed until I'm kegged up. Still experimenting...

 

[BolgBeorach]

Not a bad idea, but the garage is rather large (1800 sq ft) and I'd have to see what size I'd need. Good chance that would be an unworkable solution given the size of the space. The moisture wasn't a problem until I cold crashed so I might have to bail on the cold crashed until I'm kegged up. Still experimenting...

I can't imagine dealing with that kind of heat and humidity. It doesn't get that hot here at the height of summer. I'm basically just leaving the fermenter to
cold crash at ambient atm lol

 

[Vale71]

How about running a dehumidifier in the garage?

His cold-crashed fermenter is already a working dehumidifier.

All he needs to do is find a way to collect all that condensation water and dump it down the drain.

 

[dallasd9]

I realise that this question has been asked before, but I'm none the wiser from reading the older threads. Does cold crashing actually increase the risk of oxidation in a substantial way? I have seen posts stating that the suckback from the contracting liquid/air inside the fermentor would introduce oxygen via the airlock and thus probably cause oxidation of the beer; but doesn't oxygen enter anyway when we open it to take a hydrometer reading or to dry hop? And the amount that might enter the vessel through the airlock due to temperature change must surely be far less than that introduced when taking the whole lid off and putting something into the beer. Has anyone here experienced significant oxidation attributable to cold crashing?

I actually cold crash my beer twice before kegging. Once right after chilling my wort down to 50 degrees. I cold crash to 33 degrees over night then rack it off into the fermenter then bring it back up to pitching temperature. And the again once fermentation in complete just prior to kegging. My beers are always crystal clear and no sediment in the bottom of my keg. The first pour in clear. No wasting beer.

 

[BolgBeorach]

I actually cold crash my beer twice before kegging. Once right after chilling my wort down to 50 degrees. I cold crash to 33 degrees over night then rack it off into the fermenter then bring it back up to pitching temperature. And the again once fermentation in complete just prior to kegging. My beers are always crystal clear and no sediment in the bottom of my keg. The first pour in clear. No wasting beer.

Interesting. So the first crash drops the proteins out of suspension before the yeast is pitched, and the second crash before bottling drops most of the yeast out?

 

[Romex2121]

I actually cold crash my beer twice before kegging. Once right after chilling my wort down to 50 degrees. I cold crash to 33 degrees over night then rack it off into the fermenter then bring it back up to pitching temperature. And the again once fermentation in complete just prior to kegging. My beers are always crystal clear and no sediment in the bottom of my keg. The first pour in clear. No wasting beer.

I may have to try this , I prefer clear wort more so than trub whirling around while the yeast is going strong , sounds silly but I always think the settling trub covers the yeast on bottom of fermenter....
have you noticed anything different with the taste or quality of your beers when doing this ??
so you chill wort after boil as normal then transfer to fermenting vessel, put in
fridge/freezer (whatever you use) drop temp for a quick over night crash , transfer wort (again) off sediment to a clean vessel, allow to warm up to pitching temp , pitch yeast and ferment as normal ?

 

[Edward's Beer Cellar]

Here is a picture of my DIY CO2 harvester (there is no liquid in the jars as it wasn't in use when I took the picture and the air lock on the second jar is redundant). My 4 gal ferments will push out about 3/4 of a qt of sanitizer during fermentation and suck back about half of that on crashing. I don't use this rig every time but do use it for my hoppy brews. The tube goes into a hole drilled in the mini-fridge and connects to a carboy cap and elbow.

 

[dallasd9]

Interesting. So the first crash drops the proteins out of suspension before the yeast is pitched, and the second crash before bottling drops most of the yeast out?

Yes, exactly.

 

[dallasd9]

I may have to try this , I prefer clear wort more so than trub whirling around while the yeast is going strong , sounds silly but I always think the settling trub covers the yeast on bottom of fermenter....
have you noticed anything different with the taste or quality of your beers when doing this ??
so you chill wort after boil as normal then transfer to fermenting vessel, put in
fridge/freezer (whatever you use) drop temp for a quick over night crash , transfer wort (again) off sediment to a clean vessel, allow to warm up to pitching temp , pitch yeast and ferment as normal ?

Not exactly. I don't transfer to fermenting vessel until after the first crash in the boiling kettle. After I chill the wort I then put a co2 blanket on in and put the lid on the kettle and put it in my Keezer overnight. Then the next day I transfer to the fermenter. A lot of the proteins are left behind in the kettle. I've never had a problem with doing this and the beer always taste great with no off flavors.

 

[Vale71]

After I chill the wort I then put a co2 blanket on in and put the lid on the kettle and put it in my Keezer overnight.

Is the blanket knitted or woven? Sorry, couldn't resist...

BTW all you're doing with your process is increasing the risk of infection.

 

[brewbama]

Cold crash under CO2 pressure.

 

[Bobby_M]

Not exactly. I don't transfer to fermenting vessel until after the first crash in the boiling kettle. After I chill the wort I then put a co2 blanket on in and put the lid on the kettle and put it in my Keezer overnight. Then the next day I transfer to the fermenter. A lot of the proteins are left behind in the kettle. I've never had a problem with doing this and the beer always taste great with no off flavors.

I overchill my kettle by a few degrees, whirlpool and then put the lid on for the same reason but I've found that you can run off clear wort in as little as an hour of settling. Overnight is a little too aggressive especially regarding oxygen damage.

 

[dallasd9]

Is the blanket knitted or woven? Sorry, couldn't resist...

BTW all you're doing with your process is increasing the risk of infection.

Lol, I've never had a problem so in my opinion it's worth the risk.

 

[Vale71]

Lol, I've never had a problem so in my opinion it's worth the risk.

Again, you're not achieving anything either by chilling below pitching temp or waiting so long, so basically the risk is for nothing. How can nothing be worth anything?

 

[kenmcchord]

I overchill my kettle by a few degrees, whirlpool and then put the lid on for the same reason but I've found that you can run off clear wort in as little as an hour of settling. Overnight is a little too aggressive especially regarding oxygen damage.

I'm not sure I understand the oxygen damage statement, aren't we adding O2 to post boil wort to help our yeast friends in their efforts to convert the sugary wort to beer? Is it the length of time that O2 is available that risks oxidation?

 

[VikeMan]

I'm not sure I understand the oxygen damage statement, aren't we adding O2 to post boil wort to help our yeast friends in their efforts to convert the sugary wort to beer? Is it the length of time that O2 is available that risks oxidation?

When you oxygenate your wort at yeast pitch, the yeast take up that O2 pretty quickly, within about an hour.

 

[Bobby_M]

Is it the length of time that O2 is available that risks oxidation?

Yes

 

[kenmcchord]

Yes

Looking good @Bobby_M! And you were right to wait until after the high krausen. That was a mess for easily 4 days. It will be nice to be able to cold crash this saison.

There were chunks of yeast in that jar of starsan!