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Avoiding Cold-Side Oxidation

bobo1898

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Brewed a DIPA! Again. Cause who doesn't like a good DIPA?

Over the last twelve years of brewing, I have never cold crashed because I haven't had the luxury to do so. Well, now I do have that luxury. And I'm excited to try it.

However, I understand that the three piece airlocks are difficult in avoiding suck back than the twin bubble (or s-shaped) airlocks. I have both. But from what I'm understanding, even with the twin bubble airlocks, it sounds like the vacuum that is created, while not pulling in the liquid from the airlock, will still pull oxygen in fermenter---something we all want to avoid.

1. Is this true that oxygen will be pulled through the liquid?

I've read the Brulosophy article of the many ways to avoid this. Out of all the options, the only real immediate solution for me, assuming the twin bubble won't be effective, seems to be, to attach gas to my fermenter---I'm using the SS Brewtech Bucket.

2. If I attach gas at 1-5 PSI, should I be concerned with residual CO2 when I go to keg? Would it effectively change my kegging method? My thought was reattach an airlock after the beer reaches crashing temps before kegging.

Highest temp the beer will reach is 72-73F. I'll be crashing to 39F.
 
Neither type of air lock will prevent oxygen from being drawn into the fermenter when cold crashing. The same holds true when bottling or transferring to a keg. Unless you're doing closed transfers into a keg, you'll get some oxygen exposure. How much depends on how carefully you transfer. I've been brewing for about the same amount of time as you and have never had a problem with oxidized beer. I'm guessing you haven't either. While I am careful when transferring and keep splashing to a minimum, I still cold crash with an S type airlock in place and don't do closed transfers.

It tales time for oxidation to manifest in most styles, so I'm assuming the small amount of oxygen my beers contain isn't degrading them to a perceptible degree in the amount of time a keg lasts me. (2 to 3 weeks)

I understand that NEIPAs degrade much faster. I don't care for them or brew them, so not a problem here. I've got everything I need and, with some minor modifications could easily eliminate cold side oxygen exposure, but really see no need at present.
 
I agree with Bob, but if you really want to avoid oxygen exposure during cold crash there are ways. If your bucket can take a small amount of pressure, and you have a regulator that will work at very low pressure, then applying CO2 is an easy solution. I wouldn't worry about it throwing off any carbonation calculations. If you don't want to pressurize, you can fill a mylar balloon with CO2 and attach in place of the airlock during cold crash. You will need a a bit of stainless or other non-permeable tubing to make the connection. That might be a bit of work the first time but should be easy after that. I attach an empty balloon to a separate port next to my airlock and capture CO2 during fermentation. That is plenty to avoid any air suck-back during cold crash.

--GF
 
Thanks for the response guys! I'm leaning towards holding my breath and just crashing with foil on top.

What about a solid stopper/bung? As I said, I'm using a SS Brewtech Brew Bucket. Think it will withstand the pressure of cold crashing?
 
A solid bung would prevent O2 from being drawn into the fermenter while cold crashing, but when it's time to transfer you'd need to warm it back up to prevent the negative pressure created during the crash from causing a rapid ingress of air once the seal was broken. In the absence of an S type airlock, foil works well.
 
BOB357 said:
A solid bung would prevent O2 from being drawn into the fermenter while cold crashing, but when it's time to transfer you'd need to warm it back up to prevent the negative pressure created during the crash from causing a rapid ingress of air once the seal was broken. In the absence of an S type airlock, foil works well.

Good point. What if I replace the solid bung with an airlock once the temperature has stabilized after the cold crash?

Replace current airlock with solid bung. Cold crash. Replace solid bung with airlock for 24 hours before transferring.

Would I still need to warm it back up before transferring?
 
When you remove the solid bung to replace it with the drilled bung and airlock the air would rush in.
 
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