cold crashing and oxidation risk

[Gelding]

been having a search but can't seem to find a generally accepted opinion on whether cold crashing and resulting air suckback poses an oxidation risk

when I cold crash (in stainless fermenter) I notice quite some volume of air suckback, in fact so much I have to remove the blowoff tube from the sanitiser that its immersed in to prevent it from pulling the while lot back into the beer.

is this going to pose an oxidation risk to the finished product ? or should I not concern ?

 

[hathro]

Don't worry. Also ditch the air lock. I back off my fermenter lid a half turn and use that without an air lock. Most on here use cling film instead of a fermenter lid. Air locks are old hat. More trouble than they are worth.

 

[Goose]

I think it is significant, and probably the best discussion on the topic is on another American site here.

So before I cold crash I pump in around 20 psi of co2, seal then crash. Small amount of effort for peace of mind.

 

[Camo6]

I've never had an issue from airlock water entering the FV but didn't like it nonetheless. I have frozen the airlock water when CCing a couple of times which can be a pain. Switched to Steri-locks for cold crashing and so far so good.

Edit: oops, misread OP's post. Never worried about air drawn back into FV. How would you overcome it?

 

[manticle]

Are you noticing a flavour issue you can relate to your process or just nerding out?

 

[Gelding]

Are you noticing a flavour issue you can relate to your process or just nerding out?

probably more to the latter because in the past I had racked to keg without cold crashing, ie the cold crashing gets done in the keg however I am thinking I can achieve the same effect with less sediment in the kegs by cold crashing in the fermenter first.... but question whether there is a risk of oxidation in doing so...

 

[manticle]

In my experience there is no discernible negative effect. I cold condition in the fermenter before keg transfer. Doesn't mean there isn't one on some level but not something I'd be concerned about. Still - nerd out all you want. If you can't get nerdy on a brewing internet forum then something is amiss with the world.

 

[Brew Forky]

...... Air locks are old hat. More trouble than they are worth.

Depends on the "Gravity". Gettin nerdy

 

[yeastybrew]

Nerd time..

This is how I see it. Beer at 18C will hold 0.92 volumes of CO2, beer at 3C will hold 1.54 volumes. So if you cold crash 23 liters of beer from 18C down to 3C it will take up 1.54 - 0.92 = 0.62 volumes or 0.62 x 23L = 14.3L of CO2. If the headspace in the primary fermenter does not have 14.3L of CO2 the beer will probably take up some oxygen from the air. An easy fix could be to use a bigger fermenter with lots of headspace for the volume of beer?

I think the effects are probably subtle. It more than likely will effect beer stability over time but could also be part of the holy grail of maintaining original levels of hop aroma for more than a few weeks.

 

[Benn]

I think it is significant, and probably the best discussion on the topic is on another American site here.

Wow, 9 pages of headfuck!
Very interesting though

 

[manticle]

I only got to page 3. Heaps of hypothesising based on very little about a problem that probably doesn't exist. Got to love home brewers sometimes.

 

[Bridges]

co2 is heavier than air and the suck back would not be violent air movement so I would still think the beer would be all cozy under it's protective blanket of co2.
my 2c.

 

[Goose]

co2 is heavier than air and the suck back would not be violent air movement so I would still think the beer would be all cozy under it's protective blanket of co2.
my 2c.

CO2 is heavier than air but then O2 is also heavier than N2... if your theory was correct we'd all be dead from living in a CO2 layer on planet earth as suggested by one guy in that link above... ..

gases mix...eventually...

 

[Goose]

Heaps of hypothesising based on very little about a problem that probably doesn't exist. Got to love home brewers sometimes.

If you say so mants.

Do you also do only 30 minute mashes and boils ? :huh:

:lol:

 

[manticle]

30 minute mash for milds yes but not for anything else. 90 min boil for most beers as a matter of course. Not quite sure I follow your point or how a technique loads of people use without issue equates to turning accepted technique on its head just cos.
Everything I do in brewing, I do for a reason. I prefer to fix actual issues when I notice them rather than those someone else imagines.

 

[TheWiggman]

Moving to solutions here, but if you have an issue with water being sucked back into your fermenter through the blowoff tube then just increase the length of your tube. If it's long enough the water won't make it all the way.

 

[Goose]

30 minute mash for milds yes but not for anything else. 90 min boil for most beers as a matter of course. Not quite sure I follow your point or how a technique loads of people use without issue equates to turning accepted technique on its head just cos.
Everything I do in brewing, I do for a reason. I prefer to fix actual issues when I notice them rather than those someone else imagines.

Sure.

The point that seems to have been debated here is that sometimes we homebrewers do things in our processes that we accept are necessary because of conventional wisdom and experience. To use the example of a 30, 50 or 90 minute mash or boil, when really do we get to a point of diminishing returns ? It seems a lot of what we do in our many practices is to buy little bits of insurance with each one adding up to a policy protecting against something going wrong with the end product.

What we both know is that oxygen is the enemy after fermentation is complete. Depending on your headspace volume and fermentation temperature, you will pull in an amount of air atop your beer during the chilling process. It can be calculated (sorry same place but here on page 7) and while the real question is, how much is enough to affect taste (the answer which I do not know) it only takes me a minute or two to stuff in 20-30 psi of CO2 into the headspace prior to cold crashing so that I don't need to try and find out. Just another piece of that insurance I was talking about.

 

[manticle]

Sure. Do whatever suits your beer and process.

I do not use airlocks but cold condition everything before transfer and have not once noticed any negatives I could realistically associate with that process. There is also nothing in brewing science literature of which I'm aware that suggests cold conditioning is a likely contributor to oxidation (although the impression I get is that this in considered relevant only to airlocked carboys?).
I certainly take some precautions like using hose with hot wort because they are really easy - my original comments were mostly in regard to the 'OMG I can't dry hop any more cos jamil said so' reactions on that forum (jamil didn't say that by the way - just people love to panic)

 

[Yob]

Anyone got a DO meter?

 

[micblair]

Yes its best best practice to have an inert atmosphere when chilling the beer as it will draw in air if otherwise allowed, but not everyone can implement this level of control. Fretting about an oxygen problem that may/may not exist (unless you have a DO meter and can make direct measurements) isn't nearly as important as paying close attention to cleaning and sanitation.

But if you are still worried, ask yourself the following:

• Will there be significant cold-side mixing, splashing or transferring in the presence of oxygen?
• Is there a requirement for the beer to have a long shelf life, i.e. 6 months or more?
• Are you tasting oxidised related flavours, i.e stale, ribes, papery?
• Is your beer being forced carbonated (opposed to being re-fermented) bottled/keg then stored at elevated temperatures?
• Are you sending bottled or keg draught products interstate or overseas, unrefrigerated?
• Are you mashing under conditions which maximise LOX activity, or the inclusion of oxygen?

Anyway, I could go on. But if you answered no to most of these, then hopefully you could agree that there really isn't any issue.