Only possible thing I'll try next is using a very long blow off tube coiled up and blow off vessel situated way below the fermenter, hoping this can overcome the gravity issue. I can't stand to see air or liquid getting into my fermenter. Any ideas? Opinions on this method?
Cold Crashing. is it worth the risk with hoppy beers?
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I'm not sure what the risks you are referring to or why it would matter if its a hoppy beer or not. I Cold crash all my beers after fermentation to get as much yeast ect out of suspension.
Using a 3 part airlock it sucks what is maybe 1/2 a tsp of sanitizer into 5 gals. Any air should stay on top of the co2 layer so I don't really see how you can get any negative effect as ive never had any type of off flavors from any beers i've done this way.
Using a 3 part airlock it sucks what is maybe 1/2 a tsp of sanitizer into 5 gals. Any air should stay on top of the co2 layer so I don't really see how you can get any negative effect as ive never had any type of off flavors from any beers i've done this way.
WrQth
Well-Known Member
Calculate the shrinkage, of the fermented wort and that of the gas in the headspace, from starting temperature to cold crash temperature. Create a blow-off tube that can contain that volume and a little extra.
Air does not sit on top of CO2, they interdiffuse and mix completely (check the video below. Br2 mixes completely with air in about 30 minutes, and Br2 is about 3.6 times heavier than CO2.) If you cold crash with an airlock (or leaky fermenter), you will get air into the fermenter. To minimize potential oxidation, package as soon as possible after cold crashing, and minimize any disturbance of the fermenter.
The only way to prevent air in the headspace when cold crashing is to have a vessel that is airtight. Something like a keg or SS conical with a spunding valve set to a few psi.
[ame]https://www.youtube.com/watch?v=_oLPBnhOCjM[/ame]
Brew on
I'm trying to avoid oxygen until it's time to bottle. And I know that people say it's little to worry about, but I've had very sensitive hoppy beers lately, and eliminating oxygen seems to be the concensus.
How would I go about calculating that volume? Or estimating it?
What about capping the fermenter a few hours prior with a solid stopper, then cold crashing?
How would I go about calculating that volume? Or estimating it?
What about capping the fermenter a few hours prior with a solid stopper, then cold crashing?
Air does not sit on top of CO2, they interdiffuse and mix completely (check the video below. Br2 mixes completely with air in about 30 minutes, and Br2 is about 3.6 times heavier than CO2.) If you cold crash with an airlock (or leaky fermenter), you will get air into the fermenter. To minimize potential oxidation, package as soon as possible after cold crashing, and minimize any disturbance of the fermenter.
The only way to prevent air in the headspace when cold crashing is to have a vessel that is airtight. Something like a keg or SS conical with a spunding valve set to a few psi.
https://www.youtube.com/watch?v=_oLPBnhOCjM
Brew on
Excellent post. Myth debunked. Besides kegging do you have any suggestions that could work?
I cold crash all of my beers.
I just kegged a super hoppy extra aromatic IPA. Dry hopped for 3 days @ 72º then cold crashed and fined with gelatin for 2 days before kegging.
HUGE blast of hop aroma out of the glass.
I don't get why people think cold crashing and fining reduces hop aroma.
I just kegged a super hoppy extra aromatic IPA. Dry hopped for 3 days @ 72º then cold crashed and fined with gelatin for 2 days before kegging.
HUGE blast of hop aroma out of the glass.
I don't get why people think cold crashing and fining reduces hop aroma.
Going from 68˚F to 32˚F will cause the CO2 volume to "shrink" by about 7.33% and the beer volume to shrink by about 0.18%. If you have 5.5 gal of beer in a 7 gal fermenter, then the volume of air that will enter upon cold crashing is:
Suck back vol = 1.5 gal * 0.0733 + 5.5 gal * 0.0018 = 0.12 gal (or about a pint)
The suckback volume will actually be greater over time, since some of the CO2 in the headspace will dissolve into the beer at the colder temp.Brew on
rnm410
Well-Known Member
The liquid will not shrink a measurable amount when crashing from room temp to fridge temp, it is the gas in the head space that "shrinks". Minimizing your head space will reduce the amount of air drawn in. Calculate the volume of air drawn in by ideal gas law.
You can cap, the vacuum formed will be less than 1 psi unless you are mostly head space. Though Oxygen will slowly leak by.
Another method would be the balloon cold crash.
rnm410
Well-Known Member
Going from 68˚F to 32˚F will cause the CO2 volume to "shrink" by about 7.33% and the beer volume to shrink by about 0.18%. If you have 5.5 gal of beer in a 7 gal fermenter, then the volume of air that will enter upon cold crashing is:Suck back vol = 1.5 gal * 0.0733 + 5.5 gal * 0.0018 = 0.12 gal (or about a pint)The suckback volume will actually be greater over time, since some of the CO2 in the headspace will dissolve into the beer at the colder temp.
Brew on
Spot on and easy.
The pressure drop from cold crashing (in a sealed container) is independent of headspace volume. Ideal gas law: PV = nRT. V, n and R are constant for this situation, so P2 = P1 * T2 / T1. 68˚F = 293.15˚K and 32˚F = 273.15˚K, so:
P[32˚F] = 14.695 psi * 273.15˚ / 293.15˚ = 13.692 psi, and
Pressure drop = 14.695 psi - 13.692 psi = 1.003 psi
Pressure drop = 14.695 psi - 13.692 psi = 1.003 psi
Brew on
If you're bottling, I'd say from anecdotal personal experience (as opposed to something as solid as Doug's math), you're likely getting more O2 exposure from the process of bottling than you would be from cold crashing. Depending on process and equipment of course, but the general practice of racking from FV to an open, non-purged bottling bucket and into non-purged bottles...
My anecdotal experience being on my hoppier beers / IPAs, I've always cold-crashed the same (with an S airlock in a ferm chamber that still has a decent concentration of CO2 in - enough to take your breath if you stick your head in the chamber by the time I'm pulling the FV out in the end, after dry hopping). Bottled for about 8 years and just recently switched to kegging. My bottled IPAs/DIPAs always had a muddied hop presence where no matter the hops used, they generally / mostly devolved into the same hop flavor + sweeter malt taste.
Recently started kegging, first batch kegged (white IPA), didn't have the equipment yet to forced transfer, so I dry-hopped in FV and cold-crashed like normal. Open rack into keg after purging some with CO2 and purging along the way (still not optimal re: O2 exposure). Tasted great. Bright, clean, distinct hop flavors. We bottled about 1gal worth before racking, same way we always bottled. Ended up darker, sweeter, muddied hop flavor.
bobeer
Fermentation Specalist
I keg and I always cold crash my beer. The only reason I really cold crash is to get the c02 into the beer quicker so i can drink it sooner. It does clear out some stuff that's suspended in the beer but I don't really care if my beer is clear or not. It clears pretty well anyway after a week in the keg.
I've never have had any oxidation issues resulting from my cold crashing process. I usually use a blow off tube but when I cold crash I remove the tube and just put some plastic wring around the barb where the tube goes on the lid of the fermentor.
I've never have had any oxidation issues resulting from my cold crashing process. I usually use a blow off tube but when I cold crash I remove the tube and just put some plastic wring around the barb where the tube goes on the lid of the fermentor.
fwiw
- I cold-crash everything but my porters and stouts.
- An s-lock will not allow liquid to "suck back".
- It will, however, still allow air to enter the FV.
- If you want to avoid that, you could do something like this...
Cheers!
- I cold-crash everything but my porters and stouts.
- An s-lock will not allow liquid to "suck back".
- It will, however, still allow air to enter the FV.
- If you want to avoid that, you could do something like this...
Cheers!
Air does not sit on top of CO2, they interdiffuse and mix completely (check the video below. Br2 mixes completely with air in about 30 minutes, and Br2 is about 3.6 times heavier than CO2.) If you cold crash with an airlock (or leaky fermenter), you will get air into the fermenter. To minimize potential oxidation, package as soon as possible after cold crashing, and minimize any disturbance of the fermenter.
The only way to prevent air in the headspace when cold crashing is to have a vessel that is airtight. Something like a keg or SS conical with a spunding valve set to a few psi.
https://www.youtube.com/watch?v=_oLPBnhOCjM
Brew on
Good to know. I still think its a vary marginal amount that is getting in. I only cold crash for 3 days and then it goes into the keg. Never had any problems with off flavors or loss of hop aroma.
So you've rigged co2 to be available when the draw occurs, the balloon is to confirm that there is pressure, and I guess you're at 1psi?
Yes, yes, and closer to .5 psi - basically just got the needle off the stop.
The balloons also act as a "fuse", just in case...
Cheers!
The balloons also act as a "fuse", just in case...
Cheers!
beautiful!
Just wondering if you now swear by this method or you consider it a novelty?
I have a pair of 17cf fridges set up for fermenting and cold-carbing/conditioning, and I was already doing CO2-pushes for all transfers.
So the carboy caps and gas fittings were already on hand. All I had to do was add the balloons.
There've been a few threads in the last couple of years covering the notion of potential oxidation during cold-crashing.
Nobody around here has ever noted oxidation notes in my kegged beers, but with everything pretty much ready, I just decided to make the notion a total non-issue.
So, do I swear by it? No - I'd have to have seen some "improvement" for that.
Do I still do it? You betcha. It takes about two minutes to pull the blow-off tubes, slap on and clamp down the caps, plug the QDs on, set the controller for "crash", and not even think about oxidation...
Cheers!
So the carboy caps and gas fittings were already on hand. All I had to do was add the balloons.
There've been a few threads in the last couple of years covering the notion of potential oxidation during cold-crashing.
Nobody around here has ever noted oxidation notes in my kegged beers, but with everything pretty much ready, I just decided to make the notion a total non-issue.
So, do I swear by it? No - I'd have to have seen some "improvement" for that.
Do I still do it? You betcha. It takes about two minutes to pull the blow-off tubes, slap on and clamp down the caps, plug the QDs on, set the controller for "crash", and not even think about oxidation...
Cheers!
NathPowe
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That's some Bill Nye s**t right there. Nice work.
I like the balloon idea, but I don't have all that equipment. I'm just using a glass carboy and a regular fridge. I think running enough length of tubing to account for the air pressure decrease may be my only solution to try.
I just do not cold crash. If you have enough calcium your yeast should be floculating enough by the time it's done. At the end of my kegs there is a tiny coating of yeast. Sure home brewing is nothing like professional brewing but minimizing oxygen is our biggest challenge. In terms of hoppy beer I'm convinced that it's a major factor making beers like Pliny the Elder and Heady Topper standout. BYO had a piece that said Heady Topper in the bright tank had 1 ppb dissolved oxygen, the person measuring thought his meter was broken as he had never seen a number that low. Again if your drinking your beers in less than a month it's not going to be a huge issue, but I'm convinced bad craft beer/homebrew normally starts with poor oxygen handling. Oxygen does not always cause card board either, in my experience it muddles, ruins hop aroma, and makes for a dull flavor that isn't bright.
Cap the carboy or the bottles?
I think i read that the inward pressure can crack a carboy. Not sure if it's true or not
The happy face really sells it
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If you use plastic fermentors it's more than enough to pop them inward and potentially weaken them (think water bottle that you throw in the freezer half empty). The extent of the force really depends on how much head space there is.
Hooking up a 1psi or so CO2 supply is a great solution.
pepindavid
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Ok, here is my situation: I am brewing an IPA (brewed on April 19th). Fermentation done since almost a week, beer still sitting in the primary ( I don't do secondary). First time I have temp control: sat around 65-66 until towards the end of fermentation, and ramped up to around 70.
I dry hopped yesterday. I want to try short dry hop (48-72 hours), and I pretty much have to bottle on Sunday evening (for some other reasons). Because of all the hop in suspension, I wanted to cold crash before (especially since I now can).
It's a 4-gallon batch in a 6-gallon plastic carboy, so plenty of headspace... And I only have a 3-piece airlock. I am afraid that the air compression will suck back the Star San (that doesn't concern me too much), and lead the carboy to "implode" since it's plastic and there is quite a lof of headspace.
My plan is to remove the airlock and put a sanitized foil with a rubber band... I know I risk some oxidation, but I don't know what else to do (I don't have CO2 setup).
Any thoughts?
I dry hopped yesterday. I want to try short dry hop (48-72 hours), and I pretty much have to bottle on Sunday evening (for some other reasons). Because of all the hop in suspension, I wanted to cold crash before (especially since I now can).
It's a 4-gallon batch in a 6-gallon plastic carboy, so plenty of headspace... And I only have a 3-piece airlock. I am afraid that the air compression will suck back the Star San (that doesn't concern me too much), and lead the carboy to "implode" since it's plastic and there is quite a lof of headspace.
My plan is to remove the airlock and put a sanitized foil with a rubber band... I know I risk some oxidation, but I don't know what else to do (I don't have CO2 setup).
Any thoughts?
You will get air in the carboy whether you use an airlock or foil. Just the act of removing the airlock and replacing with foil will allow the foil method to get more air into the carboy. An airlock will not support a high enough pressure differential to cause a plastic carboy to collapse.
A 3-piece airlock will suck back at most 10 ml of liquid (a little more than 1/3 fl oz) when filled to the top "Fill Level" line (yes, I measured.)
Brew on
Based on an earlier post by someone, it looks like you might only pull in a pint or so of air, so maybe worth looking into trying to setup a very long, wide hose and sanitizer container, set way below your level of fermenter. Gravity will help fight it. I intend to try this on my next batch. But I'm going to attach this long hose and container at least a few days before to let co2 to build up in the hose.
I did the pint calculation.
Your plan will work as long as you don't have leaks elsewhere in you system. Your arrangement will set up a small negative pressure in the fermenter, so if there are leaks, air will get in.
Brew on
zippybasher
Well-Known Member
WHAT if you inflated the balloon with co2 and stuck it over the top of the carboy or on the end of the blowoff tube... Wouldn't need to have co2 hooked up at all during crashing. the balloon would just shrink... way simpler. :rockin:
FreddyMar3
Well-Known Member
I use those Mylar baloons. They'll hold the CO2 for a long time and don't get weird/shrink in the cold fridge. I just pump them up with my tank and slip tube in that connects to the bung.
Yeah....no. Unless you have huge balloons and the space to inflate them.
I tried that once - by filling the balloons until they were almost touching the fridge "ceiling", then shutting off the gas, and starting the crash.
It turns out the CO2 volume needed is not only to make up for the volumetric shrinkage of the FV contents (head space and fluid combined) during the temperature transition. It also has to handle the CO2 absorption into the beer - the rate of which increases as the temperature drops.
I set the system up as described above, and by the next morning both balloons were totally flat and partially sucked into the carboy cap ports. And at that, the beer temperature had only dropped half way from ~68°F to the target 34°F (that's expected - it takes nearly 36 hours for that fridge to drop ~11 gallons of beer ~34 degrees).
So if you're going to crash for a few days, you'll be refilling those balloons a couple of times a day, guaranteed. Which belies the "fill the balloon" approach as being superior to the "just leave the gas connected" method, imo...
fwiw, the CO2/beer interface of a 6.5g Italian glass carboy with ~5.5 gallons in it is roughly 105 square inches, verses a ball lock cornelius keg's 53...
Cheers!
Thanks for that info @day_trippr . I left the part about absorption of CO2 by the beer at lower temps out of my response because I didn't think it would happen that fast. I will need to look into this further.
Brew on
brick_haus
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I agree, constant positive co2 pressure is the solution to preventing oxidation during cold crashing and transferring. The method doesn't matter. Having a co2 bottle and regulator is a necessary investment if you brew hoppy beers (IMHO).
So far so good. I tried the long blow off tube attempt today. 1 gallon carboy has taken in nearly 7 feet of sanitized water into a 3/8" tube, but I feel confident I have avoided oxygen getting into the system. A few days before I dry hopped and attached the long blow off tube in order to "purge" it with co2. It should be nearly down into the 30's by now and liguid movement into the blow off tube has slowed dramatically. Hopefully getting to botle tomorrow or the next day and have some results in a few weeks.
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