No Suckback Blowoff System Dilemma

[Rik van den berg]

I put together this blow off system that should prevent suck back and oxygen from entering the fermenter during cold crash.




I can do two things:

1. add sanitizer to the first jar, keep the 'in' hose connected to the short tube and the 'out' hose connected to the long tube. This way the CO2 that comes out of the fermenter will fill the first jar and push the sanitizer into the second jar. Then while cold crashing, the sanitizer will be sucked back into the first jar and (in theory) CO2 will be sucked into the sanitizer out of the first jar - Potential problem: CO2 is heavier than oxygen containing air so the CO2 will enter the first jar, 'fall' to the bottom and then be sucked to the second jar, leaving air behind. This O2 contaminated air will then be sucked back into the fermenter - something i am trying to prevent from happening
2. Add sanitizer to the second jar. On the fist jar connect the 'in' hose to the long tube and the 'out' hose to the short tube. The first jar will fill up with heavy CO2 and push out the O2 containing air, filling up the jar with CO2. During cold crash the sanitizer in the second jar will be sucked back into the first jar, and the long tube will suck back sanitizer into the fermenter....

As i am re-reading all this i just figured out this:

Use method 1 - Pull up the long tube during fermentation and then push it down to the bottom during cold crash... Sometimes i just need to write it all down to figure it out I guess.

Whatever, I'm still hitting "create thread" lol

 

[CodeSection]

Very similar to the Jaybird CO2 Harvester kit from Norcal. I wonder if enough CO2 is collected with this design as opposed using a large Mylar Balloon that would collect more CO2. I understand Norcal has an ultimate system that will allow you to hook up a CO2 tank with 1 lb of pressure.

 

[mirthfuldragon]

Mylar balloon from the dollar store. Put a T in your blow-off tube, with one end going to the blow-off container and the other going into the balloon. Balloon will fill then blow-off, then on cold-crashing it will suck CO2 out of the balloon.

 

[Jtvann]

Stopped reading at "CO2 is heavier"

 

[mongoose33]

I've done the two-jar harvesting system, and the jars may not be large enough, depending on the amount of headspace. Partly that's because the beer will absorb some of that CO2 re-entering the fermenter as the beer chills.

I had difficulty with my approach using a Bigmouth Bubbler getting the system to seal effectively. There was a tiny leak somewhere that when the partial vacuum in the fermenter was formed by chilling the headspace gas, it wouldn't pull the star-san back from the second jar to the first. If you can get it to seal correctly it will work, but you're probably better off using 1/2-gallon jars than quart jars, just to ensure you don't suck back Star-San into the fermenter.

I did a poor-man's balloon thing, tying a bread bag around the airlock to capture CO2, then feed it back during cold crash. It worked.

 

[kh54s10]

When you attach a mylar balloon to a t and blowoff on the other side, how do you keep the balloon from filling with blow off crud??

 

[mirthfuldragon]

When you attach a mylar balloon to a t and blowoff on the other side, how do you keep the balloon from filling with blow off crud??

If I am using something that actually throws blow-off crud, I will wait until near the tail end of fermentation when it calms down. The blow-off is just easier to use instead of a typical plastic airlock. You can also use a normal airlock, then swap to a balloon until the balloon fills, then leave the end of the filled balloon+hose in santizier, swap back to the airlock, then swap back to the balloon-lock when you go to cold crash. Mylar balloons don't deflate, so they will stay full of CO2 for the duration.

 

[khannon]

What if you super-cool the first vessel, then you end up with liquid CO2 which you can evaporate to only suck back CO2?..

 

[LittleRiver]

When you attach a mylar balloon to a t and blowoff on the other side, how do you keep the balloon from filling with blow off crud??

I use a 6.5gal fermenter for 5gal batches, and generally ferment in the low-mid 60's Fahrenheit. Never had an issue with crud getting near the top of the fermenter.

 

[CodeSection]

I've done the two-jar harvesting system, and the jars may not be large enough, depending on the amount of headspace. Partly that's because the beer will absorb some of that CO2 re-entering the fermenter as the beer chills.

I had difficulty with my approach using a Bigmouth Bubbler getting the system to seal effectively. There was a tiny leak somewhere that when the partial vacuum in the fermenter was formed by chilling the headspace gas, it wouldn't pull the star-san back from the second jar to the first. If you can get it to seal correctly it will work, but you're probably better off using 1/2-gallon jars than quart jars, just to ensure you don't suck back Star-San into the fermenter.

I did a poor-man's balloon thing, tying a bread bag around the airlock to capture CO2, then feed it back during cold crash. It worked.

I'm guessing that you were brewing five gallon batches and had more head space than with a 10 gallon batch. With that said, would it be reasonable using 1/2 gallon jars, as you suggested, with a 10 gallon batch and not have to worry about StarSan suck back?

Is it reasonable to assume you would collect more CO2 using 1/2 gallon mason jars over an 18" Mylar balloon? I tried googling gas volumes in containers and could not find really an answer....at least an answer or calculation I could understand.

 

[mongoose33]

I'm guessing that you were brewing five gallon batches and had more head space than with a 10 gallon batch. With that said, would it be reasonable using 1/2 gallon jars, as you suggested, with a 10 gallon batch and not have to worry about StarSan suck back?

Is it reasonable to assume you would collect more CO2 using 1/2 gallon mason jars over an 18" Mylar balloon? I tried googling gas volumes in containers and could not find really an answer....at least an answer or calculation I could understand.

No, quite the opposite. A round 18" mylar baloon has more than 10 gallons of volume. Even an 8 inch round ballon has more than a gallon of volume.

 

[CodeSection]

No, quite the opposite. A round 18" mylar baloon has more than 10 gallons of volume. Even an 8 inch round ballon has more than a gallon of volume.

Wow, the pictures I have been looking at are deceiving! I guess that settles that for me. Thanks!

 

[kh54s10]

I use a 6.5gal fermenter for 5gal batches, and generally ferment in the low-mid 60's Fahrenheit. Never had an issue with crud getting near the top of the fermenter.

I use 6 gallon Better Bottle fermenters, I get blow-off in at least 25% of my fermentations.

I know that you can wait for blow off risk to end then set up a balloon collector, but I have seen pictures of setups using a tee fitting with the balloon on one side and the blow off tube on the other. There doesn't seem any way that would work if you did get any blow off.

 

[mongoose33]

I use 6 gallon Better Bottle fermenters, I get blow-off in at least 25% of my fermentations.

I know that you can wait for blow off risk to end then set up a balloon collector, but I have seen pictures of setups using a tee fitting with the balloon on one side and the blow off tube on the other. There doesn't seem any way that would work if you did get any blow off.

I have 6.5-gallon Bigmouth Bubblers; only once in about 50-some batches did I ever have blow-off. But I've been pretty close on some others. That extra .5 gallon headspace is the difference.

I don't know how that tee-fitting would work with blowoffs, either.

 

[kh54s10]

I have 6.5-gallon Bigmouth Bubblers; only once in about 50-some batches did I ever have blow-off. But I've been pretty close on some others. That extra .5 gallon headspace is the difference.

I don't know how that tee-fitting would work with blowoffs, either.

Yep, my 6.5 gallon buckets don't blow off. I got most of my Better Bottles before the Bigmouth Bubblers were introduced.

 

[CodeSection]

No, quite the opposite. A round 18" mylar baloon has more than 10 gallons of volume. Even an 8 inch round ballon has more than a gallon of volume.

I've been meaning to follow up. The Mylar balloon works really well. Here it is filling up...