Cold crashing suck back solutions

[The_Bishop]

The flaw in your shrinkage argument is that gas solubility markedly increases at cold crashing temperatures, absorbing any CO2 in the headspace and pulling more oxygen-rich air into the fermenter. This in turn will be absorbed.

 

[awoitte]

I'm reviving this thread to ask for clarification on the attached image below. So it will sanitize any oxygen that gets sucked back, so there should be no bacteria carried, only the O2. Would three mason jars make a difference? So 3 different jars contained CO2, increasing the required suck back in order for oxygen to reach the fermentor?

 

[jjw5015]

I'm reviving this thread to ask for clarification on the attached image below. So it will sanitize any oxygen that gets sucked back, so there should be no bacteria carried, only the O2. Would three mason jars make a difference? So 3 different jars contained CO2, increasing the required suck back in order for oxygen to reach the fermentor?

Not sure, but the point isn't to sanitize the oxygen, it's to keep oxygen from coming back in at all.

 

[Bobby_M]

To clarify, those dual mason jars are not going to do jack to protect the beer from oxygen. We've determined that you need at least a 1/2 gallon for a short term cold crash and if you leave it cold for more than a couple days, it wants upwards of 2-3 gallons of CO2.

 

[awoitte]

To clarify, those dual mason jars are not going to do jack to protect the beer from oxygen. We've determined that you need at least a 1/2 gallon for a short term cold crash and if you leave it cold for more than a couple days, it wants upwards of 2-3 gallons of CO2.

What if instead of the 3 piece air lock at the end of the connection you run a ball lock gas connection into a sealed/sanitized keg, with a PRV attached to the out side of the keg.. Would that allow CO2 to fill the keg, and then work in the reverse direction when the cold crash began and the fermenter began sucking inward?

 

[Loud Brewing]

Best solution to preventing suck back other than hooking your regulator directly to your FV is to fill a 2 liter bottle with co2 and use a carbcap to hook it up to your FV.

 

[don_bran321]

This is so easy. When u you start cold crashing put a solid bung in the hole. Done.

 

[awoitte]

This is so easy. When u you start cold crashing put a solid bung in the hole. Done.

And then when you open it to transfer the vacuum immediately sucks in air, or if you have a metal fermenter you then risk imploding your vessel.

That's poor advice.

 

[Alex4mula]

To clarify, those dual mason jars are not going to do jack to protect the beer from oxygen. We've determined that you need at least a 1/2 gallon for a short term cold crash and if you leave it cold for more than a couple days, it wants upwards of 2-3 gallons of CO2.

I don’t get this. I hook up a balloon that is about the size of maybe 2 gallons. Going from 61F to 33F it deflates at most one third. This is on a 6.5g carboy with 5.2g of liquid.

 

[schematix]

This is so easy. When u you start cold crashing put a solid bung in the hole. Done.

Not even close. Terrible idea.

 

[jjw5015]

This is so easy. When u you start cold crashing put a solid bung in the hole. Done.

Please post a picture of your collapsed fermenter next time you do this.

 

[str1p3s]

I was having oxygen issues in everything and nothing was working so I decided to just stop cold crashing, at least in the FV.

I (closed) transfer to the keg when fermentation appears done or close then hook up a blow off to the gas out at fermentation temps for a few more days to make sure it's done and the yeast clean up. Then hook up co2 at 1 or 2 psi to account for the pressure change and chill it down to close to freezing in order to start force carbing. I also use the floating dip tubes in the keg so I don't have to worry about picking up sludge in the bottom.

I made my first NEIPA with this method knowing it's the most susceptible to oxidation and it turned out really well. Tastes great so far and it's a bright hazy yellow (as opposed to the oxidized brown/purplish).

 

[Bobby_M]

I don’t get this. I hook up a balloon that is about the size of maybe 2 gallons. Going from 61F to 33F it deflates at most one third. This is on a 6.5g carboy with 5.2g of liquid.

Right. I said in the short term it can require up to a 1/2 gallon depending on the vessel size and headspace. Leave that cold for 3-4 days and that balloon is going to be sucked completely flat. I fully deflated a 2.5 gallon bladder over 5 days.

 

[Bobby_M]

What if instead of the 3 piece air lock at the end of the connection you run a ball lock gas connection into a sealed/sanitized keg, with a PRV attached to the out side of the keg.. Would that allow CO2 to fill the keg, and then work in the reverse direction when the cold crash began and the fermenter began sucking inward?

In order for the CO2 inside a keg to be pulled back into the fermenter, air would have to be allowed to suck back into the keg. That air would eventually mix in with the CO2 and you will get oxygen into the beer.

 

[Alex4mula]

Right. I said in the short term it can require up to a 1/2 gallon depending on the vessel size and headspace. Leave that cold for 3-4 days and that balloon is going to be sucked completely flat. I fully deflated a 2.5 gallon bladder over 5 days.

Still, not seeing that happen. I leave my carboy 4-12 days and only use 1/4 to 1/2 ballon.

 

[daveoshomebrews]

I'm reviving this thread to ask for clarification on the attached image below. So it will sanitize any oxygen that gets sucked back, so there should be no bacteria carried, only the O2. Would three mason jars make a difference? So 3 different jars contained CO2, increasing the required suck back in order for oxygen to reach the fermentor?

For what it's worth, I use this system but with larger 64 oz mason jars vs the smaller standard size. So far works well, but I tend to cold crash 2 days in fermenter for most beers before transfer.

 

[Bobby_M]

Still, not seeing that happen. I leave my carboy 4-12 days and only use 1/4 to 1/2 ballon.

I guess the laws of physics cease to exist in your brewery, or mine. I suspect that you may have a gas leak between your balloon and hose. In my setup, the connections are verifiable gas tight since I've tested them under a few psi of pressure dunked in water. I'm not the only one to observe a full 1 gallon collapse when I was using 1 gallon bladders.