Avoiding cold crash O2 suckback

[VirginiaHops1]

I stopped cold crashing to avoid possible oxidation but I recently tried doing a closed transfer to keg which completely went to hell thanks to clogged keg inlet, so I'm considering crashing again to try to make the transfer easier. I know about the balloon method, to feed CO2 back in during crash. What about using a really long blowoff tube? The tube would fill with CO2 during fermentation, then during crash that would get sucked backwards. I would just need a long enough tube so the liquid didn't make it to the fermenter. I just ordered 10 foot of tube I was going to cut up and use as blow-off. Anyone done this? I'm sure the entire 10 feet isn't needed but definitely want enough so my Starsan doesn't end up in the beer.

 

[specharka]

It might work to prevent oxygen ingress, but only until you pull the hose. Assuming that there’s a perfect seal you will encounter a good bit of vacuum pressure inside your fermenter to keep the water suspended. That can be avoided by using the balloon method or upgrading to one of these:

https://www.norcalbrewingsolutions.com/store/CO2-Carbon-Dioxide-Harvester-Kit.html

Cheers!

 

[TheHopfather]

Why not just use a balloon? It's cheap, it works.

 

[VirginiaHops1]

Why not just use a balloon? It's cheap, it works.

I need to use a blowoff on most of my batches anyways, so if I use the tubing to control suckback it's set it and forget. Vs having to go back and fiddle with the balloon after a couple days.

 

[divrack]

How about sticking the blow off tube to the bottom of a bucket inverted in a larger bucket of liquid. As the inverted bucket fills it will be a resovouir of co2, suck back will then reduce the resovouir volume..
Or, just get some cheap cornys.

 

[NGD]

Forgot where I saw this, but someone used a 1-2 ltr medical grade drainage bag that has a one way valve as their reservoir. The bag would fill with C02 and let any extra escape once full, and during cold crash the valve would prevent O2 from coming back in. Looked pretty trick!

The hose idea seems like it has a higher chance of sucking back sanitizer. Also if the negative pressure became to great it would certain expose any leaks in your system.

 

[Home_alone1]

I just slap a solid bung on and cold crash . It’s a bit of a pain to get it off later but no suck back

 

[jturman35]

No more suck back!

 

[Bobby_M]

I stopped cold crashing to avoid possible oxidation but I recently tried doing a closed transfer to keg which completely went to hell thanks to clogged keg inlet, so I'm considering crashing again to try to make the transfer easier. I know about the balloon method, to feed CO2 back in during crash. What about using a really long blowoff tube? The tube would fill with CO2 during fermentation, then during crash that would get sucked backwards. I would just need a long enough tube so the liquid didn't make it to the fermenter. I just ordered 10 foot of tube I was going to cut up and use as blow-off. Anyone done this? I'm sure the entire 10 feet isn't needed but definitely want enough so my Starsan doesn't end up in the beer.

The suck back is about 2 liters in my experience. No hose is big enough. This works. https://www.brewhardware.com/product_p/ccguardianv2.htm

 

[jack13]

...
Or, just get some cheap cornys.

^ That's what I do. Rather than cold crash and then keg, I keg and then cold crash.

 

[brew703]

What Bobby linked works. One tube goes into Starsan and the balloon will fill with natural CO2 during fermentation. I made one with a balloon because BH was out of stock and I had what I needed.

 

[matt_m]

I recently saw a post elsewhere where the guy filled the keg he planned to use for the beer with Starsan. A hose ran from the fermenter to the keg gas in. Another hose ran from the liquid out to the bottom of another open keg. As the beer fermented it pushed the Starsan out of the first keg into the second. On cold crash it sucks the gas back from the first keg and any liquid needed to replace it from the second keg. I'm thinking of giving that a try, but with the 2nd keg being a bucket and lid. Basically a giant version of the Jaybird yeast harvester with stuff you probably already have around.

 

[SmokeyRydr]

I recently saw a post elsewhere where the guy filled the keg he planned to use for the beer with Starsan. A hose ran from the fermenter to the keg gas in. Another hose ran from the liquid out to the bottom of another open keg. As the beer fermented it pushed the Starsan out of the first keg into the second. On cold crash it sucks the gas back from the first keg and any liquid needed to replace it from the second keg. I'm thinking of giving that a try, but with the 2nd keg being a bucket and lid. Basically a giant version of the Jaybird yeast harvester with stuff you probably already have around.

How did that turn out?

 

[matt_m]

Never got it set up due to a busy fall, but thanks for reminding me. Just need to buy some hose and ball locks to make it all work.

 

[SmokeyRydr]

Never got it set up due to a busy fall, but thanks for reminding me. Just need to buy some hose and ball locks to make it all work.

I'm thinking making an online balloon filler.

I just bought a hose tee and a one-way check valve.

Just before cold crashing I'll add it to my blowoff tube connecting a balloon to the open tee end and my co2 supply to the valve. Now slowly add enough pressure to fill the balloon and disconnect my supply line.

Of course, I could just add a low pressure feed from my supply, but I like the idea od the balloon.

 

[speavler]

I recently saw a post elsewhere where the guy filled the keg he planned to use for the beer with Starsan. A hose ran from the fermenter to the keg gas in. Another hose ran from the liquid out to the bottom of another open keg. As the beer fermented it pushed the Starsan out of the first keg into the second. On cold crash it sucks the gas back from the first keg and any liquid needed to replace it from the second keg. I'm thinking of giving that a try, but with the 2nd keg being a bucket and lid. Basically a giant version of the Jaybird yeast harvester with stuff you probably already have around.

this is basically what I have rigged up, but I really only use it to purge kegs with CO2. When I cold crash, I just close the valve I have attached to the lid of my fermenter, then before racking to keg, attach my CO2 to the gas post attachment and crack open the valve. See my media for a visual.

 

[millatime]

I just slap a solid bung on and cold crash . It’s a bit of a pain to get it off later but no suck back

Yup, I do the same with the solid bung on my conicals.

 

[MaxStout]

One of these, and two 1/2 gallon Mason jars. I've never had enough suckback to pull the full 1/2 gal of Starsan all the way back from the second jar into the first. Thus, no air gets back in to the fermenter, just CO2.

 

[RPh_Guy]

One of these, and two 1/2 gallon Mason jars.

Silicone lets through quite a lot of oxygen.

I'm sure it's better than open air, but I wouldn't use that.

 

[MaxStout]

Silicone lets through quite a lot of oxygen.

I'm sure it's better than open air, but I wouldn't use that.

True. But compared to the system keeping ~2L of air out of the fermenter, I'd say the amount of O2 permeating the tubing over the course of 2 weeks is trivial.

 

[Cato1507]

The suck back is about 2 liters in my experience. No hose is big enough. This works. https://www.brewhardware.com/product_p/ccguardianv2.htm

Not according to the reviews on the link.

 

[Dland]

If you keg, just keg before cold crash, no worries ever. Hit it with CO2 to make sure it is sealed first. Or keg and spund, then crash, will come out even better if you do it right.

 

[RPh_Guy]

I'd say the amount of O2 permeating the tubing over the course of 2 weeks is trivial.

It's hard to say without measuring but you'd be surprised.

Here's some measurements of stoppers...
The silicone stopper is much thicker and has much smaller surface area than silicone tubing.

 

[speavler]

Yup, I do the same with the solid bung on my conicals.

What happens when it’s time to rack?

 

[Home_alone1]

Air gets in , but it’s better than air mixing the whole time I’m lagering the beer, I also don’t do closed transfers. I’m not the most advanced brewer but I try and get by.

 

[Beer666]

Has anyone tried these plaato valves yet? https://www.plaato.io/product-page/plaato-valve

 

[millatime]

What happens when it’s time to rack?

I don't do closed transfers so I just rack to keg and purge

 

[Aristoi]

I have tried a cold crash guardian posted earlier in this thread and had similar performance to reviews posted. Worked flawless the first time and was so excited this problem was solved, second time starsan suck back into my beer, and 3rd time leaked/would not inflate. To be honest i had no idea about the trim barb update until comments in this thread pointed to reviews so I may try that next time and inspect my cap for cracks. I had high hopes for it as i really wanted an off the shelf solution i did not need to think about or build. I ended up going back to my tried and true method i have been using for years that is simple and just works!

I take no credit for this as i read about this here on HBT several years ago, but those posts are probably hard to find now. It simply calls for using a 1 gallon ziploc bag and some hose. I can take a d-rest beer from 68-70F down to 30F and still have some CO2 in the 1 gallon bag. If i had to guess suckback in my brewbucket seems to be more than my glass carboys to about 3 quarts/liters and this size bag works great.

CO2 ziploc stopper bag construction

1. You simply take a 1 gallon ziploc bag and trim the corner so that the resultant hole is slightly smaller than the hose you plan to put through. If too big start over and throw away the bag. This step is important to get a good seal. The hose will be sticky so you need to dip the tubing in starsan to lubricate. If done right the plastic bag should stretch a little and be drawn onto the tube as you reach the end of the tube.
2. Once it is dry i apply some scotch tape to keep it in place. The scotch tape wont seal, why step 1 is important. I have experimented with different tubing and attaching to OD and ID of airlocks, the tubing is not as secure and have evolved to my current version which simply is inserted directly into the stopper (with starsan as lubricant of course). The bevlex beer line is the ideal tubing for this that has the right OD to fit in stopper.

My process in use is to use normal airlock and/or blow off tube during fermentation.

1. Once beer is done and ready for cold crash i inflate the bag with a open CO2 line from the stopper end a couple of times to push out any small amounts of oxygen in the line or the flattened bag.
2. On the last, inflate bag until it is a little tight i put my thumb over stopper and walk over to my container of premade starsan i keep around to sanitize random items between brews.
3. I dunk the stopper end with my thumb over stopper and momentarily remove my thumb to get sanitizer on the bottom of stopper and in between my thumb. The positive pressure in the bag from step above will burp out a little CO2 so starsan will not enter. If for whatever reason you did not have enough pressure in the bag and some starsan entered put a little pressure on the bag and loosely take thumb off stopper to drain while pointed down.
4. I walk over to my fermenter that was preplaced in my cold crash refrigerator and quickly swap airlock with this stopper bag setup.

Enjoy!

 

[bkz]

I have a second CO2 tank that I use for miscellaneous things. When I'm ready to cold crash I pull off my blowoff tube and attach it to my CO2 tank instead. I barely let the CO2 flow into the FV and then...just let it ride.

I don't know if I'd do it with glass but works fine with brew buckets, speidels, and the fermentasaurus so far.

 

[RPh_Guy]

Has anyone tried these plaato valves yet? https://www.plaato.io/product-page/plaato-valve

It sucks in oxygen. Not good at all.

"Ziploc" bags: better than nothing but still very oxygen-permeable. They aren't even air-tight.