Cold crashing problems and questions!!!

[MannyEdwards]

Unfortunately gasses of different densities do not behave this way. Any air that is sucked in will mix and become evenly distributed with the CO2 rich fermentor headspace gas.

If gasses did behave this way there would be a nice blanket of CO2 in the lower layers of our atmosphere. Life as we know it would not exist.

Yeah, eventually, and faster if you stirred it. But like carefully pouring sugar water into pure water, they stratify and take awhile to mix. With the short times in cold crashing, I don't think it will make any difference. If you were selling beer with a one-year best by date, sure, worry about it. But this is a practical solution with a homebrew setup.

 

[BarleyStanding]

I've always pulled off the blow-off setup and popped on an airlock when primary activity is mostly finished; then crash in a fridge when its time to keg. Haven't had any O2 or other issues with this method.

 

[jddevinn]

Gases will mix quickly without any physical "mixing" assistance due to the enthalpy of the molecules in the two gases.

In the below video a sample of Bromine Br2 diffuses into a sample of air in 30 minutes (with no pressure and no temperature differential).

Diffusion rates of different gases can be ratio using Graham's Law using this ratio a similar sample size of CO2 would be completely diffused into the air sample within 40 minutes.

This is with no pressure differential. If you cold crash and do not form a completely sealed vacuum (you won't) or offset with positive pressure CO2 the pressure differential will speed this mixture.

If you have an air leak into the fermenter during fermentation, even with positive pressure in the fermenter, eventually even the high pressure will not stop air from diffusing into the fermenter. It will be even faster after active fermentation stops and CO2 is no longer being released from the beer.

I do not know where the idea of a CO2 "blanket" originated but it is 100% wrong. The only way to stop two gases from mixing is to physically keep them apart in different systems.

[ame]https://www.youtube.com/watch?v=_oLPBnhOCjM[/ame]

 

[MannyEdwards]

Really, I wouldn't worry about it. Even if it does mix, the relative volumes of air are small, the partial pressure of the O2 will be lower than in pure air, there are some antioxidants in the beer, and if the beer is good, he's going to drink it long before it starts tasting stale. Otherwise he can give it to the in-laws. But this is an easy and practical way to stop sucking blow-off back into the beer when cold crashing. It's a real-world solution to a real-world problem.

If you're distributing commercially, by all means check the O2 levels in your beer and do some shelf life testing. There's no telling how hot your beer will get, even if your distributor promises to keep it in cold storage.

If you're making the beer for competition, you need every advantage you can get, so then go ahead and lose sleep over every molecule of oxygen.

If you're a beginner looking to solve an annoying (and gross) suck-back problem in an easy, practical, inexpensive way, don't worry about sucking in a quart or two of air when cold crashing. A little air is better than blowoff.

 

[jddevinn]

Maybe it's just me but I don't see the point of using bad science and saying it is "good enough" when it's completely wrong (CO2 blanket).

...Even if it does mix, the relative volumes of air are small, the partial pressure of the O2 will be lower than in pure air,

That's not how this works. If open to the atmosphere for transfer both ways once diffused the partial pressures and relative volumes of gasses will be the same as atmospheric the CO2 does not "stick around" in the fermenter and is not nearly enough to change the atmospheric partial pressures.

If transfer is only one way (like with the airlock) the CO2 also does not stay in the fermenter air space. As the temperature drops the CO2 in contact with the beer will be absorbed into solution until the point that the beer is saturated at the partial pressure of CO2 @ temp (similiar to force carb). Unlike CO2, which has a saturation point dependent on temp and pressure , the dissolved O2 in the beer does not remain O2 but chemically bonds and changes molecules in the beer allowing more O2 to be absorbed. Because of this contact time with O2 is important as well as the O2 present. Eventually yes as new air continues to enter the fermenter the mass ratios will change as the gas that remains in the headspace is stripped of soluble gasses (however soluble gases include O2), eventually given enough time the headspace should be only insoluble gases with all the soluble gases absorbed into the beer.

For reference, Roughly 1ml of air in a 300ml bottle will give an oxygen content of 1ppm, which is probably enough to oxidize all the reductones present in a light lager beer. [Brewing Science and practice] converting and expanding to batch size, this is equivalent to ~4 cubic inches of air for a 5 gallon batch.

I understand simplifying process and working around equipment. However, I don't understand not following best practices, especially when cheap engenius solutions like day_trippr's exist, because it's "good enough" and will get drunk long before it starts to taste too stale. Before adopting positive pressure cold crashing many of my hoppy beers would change taste before they were finished.....However, I do have a multi tap system and some kegs have hung around for many months.

 

[fun4stuff]

Hey guys! This is the second batch of beer in a row I have ruined. The first was my fault. I forgot to pull the blow-off tube out of the sanitizer water when taking a sample and it sucked up half a mason jar or sanitizer water into my $120 batch of Pliny the Younger clone. I was sooooooooo bummed but it was my own fault. Anyways, I went to counseling and have moved past it..lol

Fast forward to yesterday. I had a blueberry wheat I have been messing with the recipe on that I had in the conical. It was done fermenting so I decided it was time to crash cool it with my glycol chiller. Crank the temp down to 34 degrees around 5pm, and leave for the night. We get back at around 3am, low and behold, the damn thing sucked down a whole mason jar full of sanitizer via the blow-off tube.

How am I supposed to crash cool for 48 hours if I can't leave the blow-off tube in there? If I leave it out, it will suck in oxygen for 48 hours. The only option I can think of from now on so this doesn't happen again is to hook up a line of co2 at about 2psi so it will suck that in if it needs it rather than the oxygen.

How do you guys prevent that from happening?

1. Don't dump a recipe due to a little starsan. If you search these forums there are people who have dumped over 1/2 gallon of starsan into 5 gallons with no ill effects. I've forgot dump a little out of keg and fermenter before and can vouch that no one will know the difference- they say themselves that it is fine for consumption at that high of dilution.

2. The simplest fix to cold crashing is to sanitize saran wrap then rubber band it over the carboy or starsan soaked paper towel. If you have a fermentation chamber, cold crash it slowly bringing it down to temp over 1-2 days. If you want to keep using the blow off, buy a longer hose.

 

[jddevinn]

2. The simplest fix to cold crashing is to sanitize saran wrap then rubber band it over the carboy or starsan soaked paper towel. If you have a fermentation chamber, cold crash it slowly bringing it down to temp over 1-2 days.

Simplest but not best. See the rest of the thread about air discussion. Is the contact time between the StarSan and air enough to sanitize?

 

[Homercidal]

This seems to be one of those "what works for you" processes that are prevalent in homebrewing. As usual there are "best practices" and anecdotal evidences that seem to almost contradict each other.

Aside from needlessly splashing fermented beer before or during packaging, oxidation issues vary between brewers, and taste threshold levels also vary. That makes "This is what I do and my beer turns out great!" so easy to say.

The bottom line is that with "best practices" fermentation and packaging would happen in a closed system with little or no exposure to oxygen. Depending on your preference for packaging this best practice may be difficult or impossible to perform. If you kegged, then it's not impossible, but it may be inconvenient. It really depends on your own taste threshold and what you consider to be worth the effort. Many people cold crash, letting the beer be exposed to some amount of O2 in the process and in packaging. If the beer is to be consumed rather quickly, then what's the problem?

Others obsess over eliminating any potential for any issues. It's not necessarily a matter of what's "right" and what's "wrong", but rather what the individual prefers to do to accomplish their own end result.

For me, I am careful about not splashing. I've purged kegs before filling, and also filled without purging (Although I do always push the headspace gas out with CO2 when I'm done filling.) There doesn't seem to be a noticeable difference between my batches for oxidation. But, rigging up some basic equipment and transferring beer in a closed system purged with CO2 is not going to HURT the beer either. And it can give piece of mind to the brewer if they choose to do the extra work to make and use that equipment.

It's not a question of whether Oxygen will interact with the beer if there is some suckback, or the fermentor lid is opened, or gravity sample is taken. It DOES happen! The question is "how much?", and "how much does it affect the beer?", or better yet, "Does it change the beer enough to make the brewer want to change their methods?"

The first question is dependent on the process. The second two are questions only the brewer can decide for themselves. I'll definitely be looking into ways to improve handling, not just to eliminate potential O2 exposure, but to make transfers easier as well. As has been mentioned, sometimes it's not that much more work to use "best practices".

 

[MannyEdwards]

You're the kind of guy whose beer I love to drink, bro. It's always good, and sometimes it's exceptional. I stand by my advice, though. If it was mine, and I was a beginner, and I needed a solution, I'd take the one I suggested. But I wouldn't force anyone else to do it, lol! Cheers, man.

Maybe it's just me but I don't see the point of using bad science and saying it is "good enough" when it's completely wrong (CO2 blanket).



That's not how this works. If open to the atmosphere for transfer both ways once diffused the partial pressures and relative volumes of gasses will be the same as atmospheric the CO2 does not "stick around" in the fermenter and is not nearly enough to change the atmospheric partial pressures.

If transfer is only one way (like with the airlock) the CO2 also does not stay in the fermenter air space. As the temperature drops the CO2 in contact with the beer will be absorbed into solution until the point that the beer is saturated at the partial pressure of CO2 @ temp (similiar to force carb). Unlike CO2, which has a saturation point dependent on temp and pressure , the dissolved O2 in the beer does not remain O2 but chemically bonds and changes molecules in the beer allowing more O2 to be absorbed. Because of this contact time with O2 is important as well as the O2 present. Eventually yes as new air continues to enter the fermenter the mass ratios will change as the gas that remains in the headspace is stripped of soluble gasses (however soluble gases include O2), eventually given enough time the headspace should be only insoluble gases with all the soluble gases absorbed into the beer.

For reference, Roughly 1ml of air in a 300ml bottle will give an oxygen content of 1ppm, which is probably enough to oxidize all the reductones present in a light lager beer. [Brewing Science and practice] converting and expanding to batch size, this is equivalent to ~4 cubic inches of air for a 5 gallon batch.

I understand simplifying process and working around equipment. However, I don't understand not following best practices, especially when cheap engenius solutions like day_trippr's exist, because it's "good enough" and will get drunk long before it starts to taste too stale. Before adopting positive pressure cold crashing many of my hoppy beers would change taste before they were finished.....However, I do have a multi tap system and some kegs have hung around for many months.

 

[jddevinn]

You're the kind of guy whose beer I love to drink, bro. It's always good, and sometimes it's exceptional. I stand by my advice, though. If it was mine, and I was a beginner, and I needed a solution, I'd take the one I suggested. But I wouldn't force anyone else to do it, lol! Cheers, man.

Thanks man. I suppose my point is if compromises are made in the process due to lack of equipment, time or simply because the brewer feels like the impact is minimal to ignore.... I want them to realize that it is a compromise and not a best practice. Nothing wrong with taking a compromise when it meets your needs, but it's always best to know that it was taken.

If you're the random guy that happens to have millions of $$$ and wants to make beer, only drinks once a week. Makes an 2xIPA and 2 months down the road is looking for reasons its tastes stale do you want to find the thread that says .01ppm or less O2 is optimal and process exceptions are sometimes necessary or the thread that says let the air in during cold crash "its no problem" (as long as you don't have a high taste threshold for O2 off products, you drink the beer quickly, certain styles are made, extra)

 

[MannyEdwards]

Well, I'll be the first to admit that I have been absolutely certain about something, only to find I was wrong. At this point, I'm pretty sure nobody really knows what the hell is going on in brewing, not completely. It's a biochemical process, and it's impenetrably complex. You can control some variables to some extent and thereby get more or less consistent results, but by now I think it should be clear that you'd need divine omniscience to understand it completely.

Best practices is a useful guideline in the right context. If you're looking for best practices, I'd probably give you and some others a ring. It depends on how costly the risk of error is. In a commercial or competitive context, it's potentially very costly, and painstaking efforts to avoid oxidation are very sensible. In a beginner home brewing context, not so much, and because there are many variables and procedures to learn, maybe a beginner actually benefits by worrying about the main things first, and then start tinkering with the fringe variables as he gains experience.

It's a question of context. Are you just learning to drive? Or are you just learning to NASCAR? I'm in a home brewing group on facebook. One day a newbie proudly uploaded a picture of his very first beer, an IPA. One member offered his only comment: "Put it in a proper IPA glass." That's it. That's all he had to say. The newbie said he had broken his and was buying another when he got his paycheck. I thought, jeez. I told the newbie it's true the glass is relevant to the experience, but the main thing is to put it in a clean vessel and get it down your throat, so don't listen to that jackass.

All theoretical and procedural considerations aside, my actual experience is that my procedure does not result in oxidation before I drink the beer. That being the case, whatever the explanation and whatever "best practices" might be in another context, if a beginner is getting discouraged because he keeps sucking back his blowoff when he cold crashes, I would tell him relax, don't worry, try my simple method and get that sh*t in a glass, bro! Cheers!

 

[blizz81]

I'm up to speed on the myth of the CO2 blanket and whatnot. I get all that.


Here's a wrinkle of questioning I don't see discussed too often: even if I open my ferm chamber (chest freezer) up a few times over the course of a ferment, it sure seems like there's still a lot of CO2 in there. Obviously more towards the bottom of the chamber, but for those of you with chambers that have tried to / had to stick your head in the bottom of the chamber for some reason during peak ferment or not long after (or for those of you without and have buckets, if you've stuck your head in and taken a big whiff immediately after you open the lid for the first time after primary fermentation), you have experienced as I have the concentration of CO2 that your lungs and body can't deal with for very long.


When people measure ppm of O2 re: oxygen exposure in homebrewing, are they factoring this in? It sure seems like that environment is still heavy with CO2 in there. Generally even after I cold crash, and I usually only cold crash if I'm dry-hopping or otherwise want to pull some addition down into compacted trub.

 

[kombat]

for those of you with chambers that have tried to / had to stick your head in the bottom of the chamber for some reason during peak ferment

Oh heck yeah! I only made that mistake once. Wasn't thinking/expecting it, and darn near passed out (seriously).

Now if I need to reach into my ferm chamber for some reason while there's beer in there (swapping out the dehumidifier, cleaning up a spill, whatever), I take a deep breath before leaning in.

 

[jddevinn]

I'm up to speed on the myth of the CO2 blanket and whatnot. I get all that.


Here's a wrinkle of questioning I don't see discussed too often: even if I open my ferm chamber (chest freezer) up a few times over the course of a ferment, it sure seems like there's still a lot of CO2 in there. Obviously more towards the bottom of the chamber, but for those of you with chambers that have tried to / had to stick your head in the bottom of the chamber for some reason during peak ferment or not long after (or for those of you without and have buckets, if you've stuck your head in and taken a big whiff immediately after you open the lid for the first time after primary fermentation), you have experienced as I have the concentration of CO2 that your lungs and body can't deal with for very long.


When people measure ppm of O2 re: oxygen exposure in homebrewing, are they factoring this in? It sure seems like that environment is still heavy with CO2 in there. Generally even after I cold crash, and I usually only cold crash if I'm dry-hopping or otherwise want to pull some addition down into compacted trub.

If you are fermenting in say a chest freezer while the freezer is closed it is sealed to the outside environment so that the Co2 discharge from fermentation increases the CO2 concentration in the freezer. Once you open the lid it starts dissipating into the atmosphere. As soon as you open the lid and can smell the CO2 some of it has made it to your nose.

 

[blizz81]

If you are fermenting in say a chest freezer while the freezer is closed it is sealed to the outside environment so that the Co2 discharge from fermentation increases the CO2 concentration in the freezer. Once you open the lid it starts dissipating into the atmosphere. As soon as you open the lid and can smell the CO2 some of it has made it to your nose.

Sure, but like I said, it still seems fairly heavy with CO2 even after I've cold crashed a brew, which has entailed me opening it probably to check on primary ferment at least once, and also (in my case of cold crashing), to dry hop / add something. I'm not saying there's no O2 in there, but I'm thinking there's less than if we had doug calculate an estimated ppm in a more "open" environment. And / or how much more negligible that level of O2 exposure would be.


Not saying the positive pressure methods here aren't best-practice, which I appreciate the info and ideas as an option.

 

[AZCoolerBrewer]

I don't really know for sure, but my gut tells me that there are just as many crazy oxidation guys out there as there is crazy sanitation guy. Just nobody has found crazy CO2 purge oxidation guy's video yet.ipe:

 

[whoaru99]

Doesn't matter the hobby, there is always going to be some contingent having OCD.

Brewing is moderate from what I've seen so far. Wanna see some OCD mofos, get into audio (which, BTW, is another of my bigger hobbies).

 

[fun4stuff]

Sure, but like I said, it still seems fairly heavy with CO2 even after I've cold crashed a brew, which has entailed me opening it probably to check on primary ferment at least once, and also (in my case of cold crashing), to dry hop / add something. I'm not saying there's no O2 in there, but I'm thinking there's less than if we had doug calculate an estimated ppm in a more "open" environment. And / or how much more negligible that level of O2 exposure would be.


Not saying the positive pressure methods here aren't best-practice, which I appreciate the info and ideas as an option.

Obviously if oxidation was a huge risk, no one would recommend opening to check gravity or cold crashing. Tons of people open multiple times to check gravity and/or cold crash without any oxidation issues. Obviously, you want to be careful when doing this to minimize oxygen exposure, but there's no point spending too much time worrying about it.

If it was a real world issue, then the practice of cold crashing and taking multiple gravity readings wouldn't be so common place.

Hell, transferring to a secondary exposes the beer to even more oxygen and people did that for years (still do it for dry hopping or fruit) and oxidation still was/is not that common. Do whatever helps you gets your jollys, but you're probably wasting your time if you don't plan on aging the beer for years. Just rubber band it with some plastic, realizing the risk of oxidation was lower than the probability of improving the clarity of your beer (benefits outweigh risks).

 

[day_trippr]

I dunno, from some of the home brew I've tasted over the years, oxidation plays a much larger role in most home brewers pursuits than they realize...

Cheers!

 

[whoaru99]

I dunno, from some of the home brew I've tasted over the years, oxidation plays a much larger role in most home brewers pursuits than they realize...

Cheers!

Your implication is that ingress through the airlock is the prime factor?

 

[day_trippr]

Your implication is that ingress through the airlock is the prime factor?

Actually, you can't find any specific modality implied or expressed...

Cheers!

[edit] But as you did kinda ask...I expect the contribution of post-fermentation air ingress via air-lock is a minor player compared to the lead role: bad racking technique, which would include "un-purged receiver" as the major character defect that makes every other potential process flaw (eg: splashing) even worse...

 

[Horseshoot]

If there's any O2 in the headspace, the O2 will evenly mix with the CO2. It doesn't matter that CO2 is more dense than what gets sucked in. The molecules bounce around and all of the gasses will evenly mix. You then have O2 in contact with the beer. It sounds like the OP is trying to eliminate all O2 exposure. An S shaped airlock isn't going to do what he wants.

CO2 is denser that O2. It will settle lower than O2. Every time. So, it will crete a blanket of C02, over the beer.

Mike

 

[day_trippr]

CO2 is denser that O2. It will settle lower than O2. Every time. So, it will crete a blanket of C02, over the beer.

Mike

No, it won't. Never, ever, ever.
If it did, neither of us would be here right now.

And here's why..

Cheers!

 

[Horseshoot]

Co2 "blanket" is always brought up in these discussions. There is no Co2 blanket. Mixture by enthalpy will result in the Co2 diffusing into the air very quickly. Even without any chemistry knowledge....if Co2 didn't diffuse in the air why doesn't our breath cause a Co2 "blanket" to form in spaces with large amounts of people?[/QUOTE]

C02 is heavier. It settles. Into the low spaces. In certain open heart surgeries, C02 is introduced into the chest in order to prevent air from entering open vessels. And it works. The blanket concept is real.

Mike

 

[day_trippr]

No, it doesn't. What you are describing is a procedure where there is a constant flow of CO2 flooding the area and physically displacing other gases. It's a temporary condition that ceases to exist once the gas flow is shut off.

And it has zero relationship to the static condition that exists in a fermenter or keg...

Cheers!

 

[Horseshoot]

I don't really know for sure, but my gut tells me that there are just as many crazy oxidation guys out there as there is crazy sanitation guy. Just nobody has found crazy CO2 purge oxidation guy's video yet.ipe:

^ This...

Mike

 

[Horseshoot]

Doesn't matter the hobby, there is always going to be some contingent having OCD.

Brewing is moderate from what I've seen so far. Wanna see some OCD mofos, get into audio (which, BTW, is another of my bigger hobbies).

^ HAHAHA!! And this! My best bud is an audio guy!

Mike

 

[ChelisHubby]

I just take off the bubbler and put on foil when I cold crash as the tempature and the air in the fridge are a hard place for a infection to breed or live! 120 dllrs for a batch would be painful!

 

[Horseshoot]

No, it won't. Never, ever, ever.
If it did, neither of us would be here right now.

And here's why..

Cheers!

I worked 12 years in an environment (open heart surgery) that proves it does create a blanket.

Mike

 

[Horseshoot]

No, it doesn't. What you are describing is a procedure where there is a constant flow of CO2 flooding the area and physically displacing other gases. It's a temporary condition that ceases to exist once the gas flow is shut off.

And it has zero relationship to the static condition that exists in a fermenter or keg...

Cheers!

During fermentation there isn;t a constant flow of C02?

Mike

 

[jddevinn]

Co2 "blanket" is always brought up in these discussions. There is no Co2 blanket. Mixture by enthalpy will result in the Co2 diffusing into the air very quickly. Even without any chemistry knowledge....if Co2 didn't diffuse in the air why doesn't our breath cause a Co2 "blanket" to form in spaces with large amounts of people?

C02 is heavier. It settles. Into the low spaces. In certain open heart surgeries, C02 is introduced into the chest in order to prevent air from entering open vessels. And it works. The blanket concept is real.

Mike[/QUOTE]

No it doesn't. This is basic physics. I'm not "postulating" possibilities here. I have physics and mechanical engineering degrees and consider gas mixtures every day for work, I know what I am talking about. If you lay on the ground do you die because you are in a CO2 blanket and can't breath?

Constant supply of a gas during surgery or during welding is different then what we are talking about. If higher molecular weight gasses formed a blanket a constant supply would be unnecessary.

 

[day_trippr]

You're falling behind - PKU

And your conflating two different physical paradigms still doesn't apply...

Cheers!

 

[bob1852]

Your implication is that ingress through the airlock is the prime factor?

Betterbottle's website had some cool data on how much oxygen actually makes it through the plastic in a airlock and bung, not just through the liquid...

http://www.better-bottle.com/technical.html

(Click on the permeability tab)

 

[jddevinn]

During fermentation there isn;t a constant flow of C02?

Mike

I alluded to this earlier in the thread. Do I need to do the math to show that on the level we are talking about the CO2 produced is way way less than the dissipation rate of an open system? Even if the system is not open the ppm concentration of 02 required for oxidation effects (especially in lighter beer) is low enough that it doesn't matter?

 

[iijakii]

I use a low pressure propane regulator which puts 0.4 psi on the fermenter during crashing. Nothing goes in but CO2.

Have a link?

 

[bob1852]

During fermentation there isn;t a constant flow of C02?

Mike

That's not a CO2 "blanket", it's a function of positive pressure.

Once fermentation is done, there's no longer a flow of CO2, and any O2 that enters by whatever means will mix with whatever CO2 is left.

 

[day_trippr]

Have a link?

Awesome bling aside, you can pick up a .5 psi gas regulator at any big box hardware store in the gas grill parts aisle...

Cheers!

 

[iijakii]

Awesome bling aside, you can pick up a .5 psi gas regulator at any big box hardware store in the gas grill parts aisle...

Cheers!

Thanks, I'll do that. I know when I was ebay searching awhile back I kept finding propane ones but didnt stop to think about it's all the same. Ill pick one up and start cold crashing in the fermenter again one of these days. I dont keep the keezer too cold so it doesnt have the same effect cold crashing in the keg.

 

[kevink]

Have a link?

It works great. You will love it. It even works when dumping trub if you have a conical. Instead of removing the airlock or blowoff and letting air in when you dump, you use this and the volume lost is replaced with CO2 instead of air.

http://www.amazon.com/gp/product/B00KTS20JM?psc=1&redirect=true&ref_=od_aui_detailpages01

 

[kevink]

Awesome bling aside, you can pick up a .5 psi gas regulator at any big box hardware store in the gas grill parts aisle...

Cheers!

I looked at those stores, but all of the regulators were more expensive and had permanently attached propane tank fittings and/or hoses which wouldn't have worked. The one I linked to has standard female NPT threads on the inlet and outlet which is what you want. Plus, the ones at my local stores were cheap quality, uncoated, and can't be disassembled.