Author Topic: Cold Crashing  (Read 1107 times)

Offline denny

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Re: Cold Crashing
« Reply #15 on: December 06, 2013, 10:51:19 AM »
just a little bit- my latest IPA is not quite as hoppy in aroma as usual, though not what I would consider oxidized.

I'd just read another brewer, whom I respect, being very OCD about crashing his IPAs and how he feels he oxidized one by crashing with too much head space in the fermentor, which got me thinking.

Lately, I've been crashing in the primary on a lot of beers to get the cleanest/clearest beer possible in the keg, but maybe I will go back to transferring to a keg, dryhopping and then crashing/carbing.

I've gotta say that explanation doesn't make a lot of sense to me.
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Offline blatz

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Re: Cold Crashing
« Reply #16 on: December 06, 2013, 11:14:06 AM »
just a little bit- my latest IPA is not quite as hoppy in aroma as usual, though not what I would consider oxidized.

I'd just read another brewer, whom I respect, being very OCD about crashing his IPAs and how he feels he oxidized one by crashing with too much head space in the fermentor, which got me thinking.

Lately, I've been crashing in the primary on a lot of beers to get the cleanest/clearest beer possible in the keg, but maybe I will go back to transferring to a keg, dryhopping and then crashing/carbing.

I've gotta say that explanation doesn't make a lot of sense to me.

i guess he feels the suck back as the beer cools brings in oxygen into the beer.  I'm having a hard time figuring out if this is really a problem or not - hence why I'm posing the question to the collective wisdom of the forum.
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Offline blatz

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Re: Cold Crashing
« Reply #17 on: December 06, 2013, 11:15:14 AM »
have you ever noticed whether or not cold crashing in the fermentor oxidizes your beer?

By the time I'm cold crashing, whatever vessel I do it in is sealed.  There's no chance for O2 to enter.

air does vacuum in through the airlock.  i do have a couple of those stoppers like steve linked above.  maybe I should just use those...
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Online morticaixavier

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Re: Cold Crashing
« Reply #18 on: December 06, 2013, 11:16:32 AM »
have you ever noticed whether or not cold crashing in the fermentor oxidizes your beer?

By the time I'm cold crashing, whatever vessel I do it in is sealed.  There's no chance for O2 to enter.

air does vacuum in through the airlock.  i do have a couple of those stoppers like steve linked above.  maybe I should just use those...

the air is still gonna get in when you remove the stopper. I just can't imagine it's a big deal but it should be easy to test with a split 10 gallon batch, half kegged then crashed the other crashed then kegged.

to be fair you would want to wait say 1 month after kegging to see if there is actually any difference.
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Offline denny

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Re: Cold Crashing
« Reply #19 on: December 06, 2013, 11:51:56 AM »
have you ever noticed whether or not cold crashing in the fermentor oxidizes your beer?

By the time I'm cold crashing, whatever vessel I do it in is sealed.  There's no chance for O2 to enter.

air does vacuum in through the airlock.  i do have a couple of those stoppers like steve linked above.  maybe I should just use those...

Yeah, but why are you using an airlock when you cold crash?  Fermentation is done, there's no need for it.  I either keg to cold crash or seal the fermenter.
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Offline denny

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Re: Cold Crashing
« Reply #20 on: December 06, 2013, 11:53:13 AM »
the air is still gonna get in when you remove the stopper. I just can't imagine it's a big deal but it should be easy to test with a split 10 gallon batch, half kegged then crashed the other crashed then kegged.

to be fair you would want to wait say 1 month after kegging to see if there is actually any difference.

The stopper won't be removed until after the cold crashing.  At that point, why is it any different than not crashing and removing the stopper?
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Offline blatz

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Re: Cold Crashing
« Reply #21 on: December 06, 2013, 11:58:15 AM »
Yeah, but why are you using an airlock when you cold crash?  Fermentation is done, there's no need for it.  I either keg to cold crash or seal the fermenter.

never put much thought to it.  guess i will just use a stopper from now on.  i assume that's what you mean by 'seal'. 
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Re: Cold Crashing
« Reply #22 on: December 06, 2013, 12:08:28 PM »
the air is still gonna get in when you remove the stopper. I just can't imagine it's a big deal but it should be easy to test with a split 10 gallon batch, half kegged then crashed the other crashed then kegged.

to be fair you would want to wait say 1 month after kegging to see if there is actually any difference.

The stopper won't be removed until after the cold crashing.  At that point, why is it any different than not crashing and removing the stopper?

because there is now a pressure differential between the inside of the fermenter and the outside. It will always exist if you cold crash because the air inside (and liquid) are contracting. If you have an air lock in place, it equalizes as the air cools sucking air in. if you seal the fermenter it is not able to equalize until you open unseal it but it will equalize by sucking in air when you unseal it.

I suppose though, that the reduced time of contact between the air and the beer could have an impact. if you have the fermenter 'open' the beer is potentially in contact with o2 for the whole cooling process while if you seal the fermenter it is only in contact with o2 for the short time between opening and purging in the keg.
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Offline HoosierBrew

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Re: Cold Crashing
« Reply #23 on: December 06, 2013, 12:19:00 PM »
I prefer to rack to keg, top off with CO2, then crash and charge at same time.

+1

+2
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Offline mugwort

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Re: Cold Crashing
« Reply #24 on: December 06, 2013, 12:19:59 PM »

because there is now a pressure differential between the inside of the fermenter and the outside. It will always exist if you cold crash because the air inside (and liquid) are contracting. If you have an air lock in place, it equalizes as the air cools sucking air in. if you seal the fermenter it is not able to equalize until you open unseal it but it will equalize by sucking in air when you unseal it.

I suppose though, that the reduced time of contact between the air and the beer could have an impact. if you have the fermenter 'open' the beer is potentially in contact with o2 for the whole cooling process while if you seal the fermenter it is only in contact with o2 for the short time between opening and purging in the keg.

Very well said.
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Offline denny

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Re: Cold Crashing
« Reply #25 on: December 06, 2013, 01:32:58 PM »
Yeah, but why are you using an airlock when you cold crash?  Fermentation is done, there's no need for it.  I either keg to cold crash or seal the fermenter.

never put much thought to it.  guess i will just use a stopper from now on.  i assume that's what you mean by 'seal'.

Yep.
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Offline denny

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Re: Cold Crashing
« Reply #26 on: December 06, 2013, 01:35:02 PM »
because there is now a pressure differential between the inside of the fermenter and the outside. It will always exist if you cold crash because the air inside (and liquid) are contracting. If you have an air lock in place, it equalizes as the air cools sucking air in. if you seal the fermenter it is not able to equalize until you open unseal it but it will equalize by sucking in air when you unseal it.

I suppose though, that the reduced time of contact between the air and the beer could have an impact. if you have the fermenter 'open' the beer is potentially in contact with o2 for the whole cooling process while if you seal the fermenter it is only in contact with o2 for the short time between opening and purging in the keg.

I can't imagine that will make any difference.  The O2 will sit on top of the beer, right?
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Re: Cold Crashing
« Reply #27 on: December 06, 2013, 01:50:58 PM »
because there is now a pressure differential between the inside of the fermenter and the outside. It will always exist if you cold crash because the air inside (and liquid) are contracting. If you have an air lock in place, it equalizes as the air cools sucking air in. if you seal the fermenter it is not able to equalize until you open unseal it but it will equalize by sucking in air when you unseal it.

I suppose though, that the reduced time of contact between the air and the beer could have an impact. if you have the fermenter 'open' the beer is potentially in contact with o2 for the whole cooling process while if you seal the fermenter it is only in contact with o2 for the short time between opening and purging in the keg.

I can't imagine that will make any difference.  The O2 will sit on top of the beer, right?

I suspect it's all academic anyway. I know that oxidation is one of the very last things I worry about in my homebrewery most of the time given that I own three kegs and there are 4 adults in my house. A keg very very rarely lasts long enough to get over the hill much less oxidized seriously.
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Offline klickitat jim

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Re: Cold Crashing
« Reply #28 on: December 06, 2013, 02:40:32 PM »
Yes academic IMO
The headspace by the time for cold crashing is about 100% CO2, if the beer shrinks 5%, you draw in 5% air which I'd 20% o2. Pretty infinitesimal. Plus co2 is heavier than o2. I doubt a lab test would show much difference in total dissolved o2.

Offline HoosierBrew

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Re: Cold Crashing
« Reply #29 on: December 06, 2013, 03:07:09 PM »
I think the keg blanketed with CO2 is superior for crashing, followed by a stoppered bucket or carboy ( did this for a while and had good results too) second, with the airlock sucking in air dead last. I started crashing in keg because I felt in theory the oxidation was less, though in practice the stopper worked fine. I did feel crashing in a FV with an airlock caused an oxidized beer or two though. Maybe not.
« Last Edit: December 06, 2013, 03:09:32 PM by HoosierBrew »
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