Closed system / C02 transfers

[mongoose33]

The key to purging the keg with water/sanitizer is to:
1. Fill the keg as completely as possible to displace as much air as possible.
2. Replace as much of the water/sanitizer as possible with CO2 (or another inert gas).

With corny kegs there are 2 pitfalls to #1.
-First, the gas dip tube sits about 1/2" into the keg. This means any air above that point won't make it out.
-Second, the lid is a huge reservoir for air. The PRV valve also sits down about 1/2" into the lid so anything above that point can't be removed either with standard length gas dip tube.

Here's how I resolve this problem:

When I'm transferring the Star-San from the target keg to another, as the target keg empties it drives bubbles into the second keg from the bottom of the OUT dip tube. This creates a lot of bubbles of....you guessed it...CO2.

I let it bubble by connecting/disconnecting the QD on that OUT side. When I get the headspace full of bubbles, then I insert the lid sidewaysinto those bubbles, keeping them coming up from the bottom. The end result is a headspace that is full of CO2 bubbles, NOT air.

And thus that keg, which will be the target keg next time, is full of Star San and CO2. When it comes time to purge it, same deal--what's left over is CO2.

Doing this I don't need to trim the dip tube.

 

[schematix]

Here's how I resolve this problem:



When I'm transferring the Star-San from the target keg to another, as the target keg empties it drives bubbles into the second keg from the bottom of the OUT dip tube. This creates a lot of bubbles of....you guessed it...CO2.



I let it bubble by connecting/disconnecting the QD on that OUT side. When I get the headspace full of bubbles, then I insert the lid sidewaysinto those bubbles, keeping them coming up from the bottom. The end result is a headspace that is full of CO2 bubbles, NOT air.



And thus that keg, which will be the target keg next time, is full of Star San and CO2. When it comes time to purge it, same deal--what's left over is CO2.



Doing this I don't need to trim the dip tube.

Interesting approach. I can see this working reasonably well. Definitely better than a water purge with standard dip tube.

 

[day_trippr]

fwiw, all of my kegs have full-length Out dip tubes properly positioned in their keg bottom wells.
When I purge a keg I snap the lid on, flip the keg up-side-down, and fill through the gas post while running out via the beer post into a sanitized pail.
When the run-off is bubble-free (with some rocking to encourage the last few bubbles to escape) the keg is ready...

Cheers!

 

[Rob2010SS]

Inspired by another thread I had an idea and wanted to run it by you guys. What about a closed loop closed transfer? Flush and slightly pressurize your keg with co2, attach a liquid line to your racking cane, attach a gas line to the other nipple on carboy cap, attach both these lines to the (slightly) pressurized keg, hit your relieve valve just enough to get the siphon started. Closed loop! Would this work? If so what would a safe psi on the keg be for a plastic carboy?

If that wouldn't quite work could you just apply pressure to the carboy from your charged keg, then manually depress the liquid valves plunger with a screw driver until wort is pushed to the end of the tube, spritz with starsan, attach to keg and let the siphon effect take over and boom! you got closed loop closed transfer?

I would normally just go test it out by my carboys are occupied at the moment.

(edit) Google says that a person can blow around 2 - 2.5 psi, and we can get the sterile siphon starter going... so there's that.

So I think I'm about to give this method a shot. Just want to double check with those that have done this. Is the first method mentioned here safe with a glass carboy? What's the most amount of pressure you'd want to have in a keg in order to keep the carboy from blowing up?

Thanks.

 

[schematix]

So I think I'm about to give this method a shot. Just want to double check with those that have done this. Is the first method mentioned here safe with a glass carboy? What's the most amount of pressure you'd want to have in a keg in order to keep the carboy from blowing up?

Thanks.

You'll have a hard time getting the carboy cap to stay on with more than about 1-2 psi.

 

[Rob2010SS]

Even with a hose clamp around it?

 

[h22lude]

If you used deoxygenated water this wouldn't be a huge concern (but even i have my limits as to what i'll do). The better solution is to rack at the tail end of fermentation with a few gravity points remaining so you can spund, OR prior to racking to the serving keg you can add the priming sugar directly to the fermenter. Once fermentation has kicked back off then you transfer.

I have been purging my kegs like you mentioned except I don't try to get that air bubble out. I still think I have some oxidation issues. My next batch I'm going to add some priming sugar at the end of fermentation and transfer to the purged keg the next day to see how that goes.

Just making sure I understand correctly...

Option 1) Add sugar to the beer right before it is done fermenting and transfer to a purged keg. Add a spunding valve and let it condition for another week or so. Then start carbing in that same keg (or transfer to another purged keg, then carb).

Option 2) Let beer ferment and condition in primary as normal (2 weeks). Add sugar to primary the day before kegging. The next day transfer to purged keg and carb right away.

How much sugar would you add for option 2?

fwiw, all of my kegs have full-length Out dip tubes properly positioned in their keg bottom wells.
When I purge a keg I snap the lid on, flip the keg up-side-down, and fill through the gas post while running out via the beer post into a sanitized pail.
When the run-off is bubble-free (with some rocking to encourage the last few bubbles to escape) the keg is ready...

Cheers!

I can't picture how this works. How can liquid come out with the keg upside and fully closed?

Even with a hose clamp around it?

I no expert but I'd think using a hose clamp would be bad. If you add too much pressure, the cap will pop off. With a hose clamp, it can't pop off and the only other way for the pressure to exit the carboy is to break it open.

 

[Rob2010SS]

I no expert but I'd think using a hose clamp would be bad. If you add too much pressure, the cap will pop off. With a hose clamp, it can't pop off and the only other way for the pressure to exit the carboy is to break it open.

https://www.homebrewtalk.com/showthread.php?t=516823

Look at post #5 here from day trippr. he has hose clamps on his carboy caps to secure them to the carboy.... Not being argumentative. i just want to introduce this into my process to see how it goes but I want to do it safely. I don't want to end up going to the hospital or having a mess on my floor, lol.

 

[h22lude]

https://www.homebrewtalk.com/showthread.php?t=516823

Look at post #5 here from day trippr. he has hose clamps on his carboy caps to secure them to the carboy.... Not being argumentative. i just want to introduce this into my process to see how it goes but I want to do it safely. I don't want to end up going to the hospital or having a mess on my floor, lol.

Oh I know people do it, I'm just saying it may not be safe. I wouldn't do it but I err on the side of caution.

 

[day_trippr]

[...]When I purge a keg I snap the lid on, flip the keg up-side-down, and fill through the gas post while running out via the beer post into a sanitized pail.
When the run-off is bubble-free (with some rocking to encourage the last few bubbles to escape) the keg is ready...

I can't picture how this works. How can liquid come out with the keg upside and fully closed?

"Fill through the gas post while running out via the beer post"

As for the band clamp, pressurizing a carboy, etc, I never use higher pressure than what a normal human being can generate with their lungs (~1.5 psi).
I really don't think a human could explode a carboy, though I admit I could be wrong.

Anyway, a bit above 1 psi is all that's needed to get flow started, and once the line is running clear I dial the pressure down to just above the stop, letting gravity move the beer and just using gas to backfill and keep the pressure positive...

Cheers!

[edit] The other motivation to go slow with the transfer is trying to end up with almost zero pressure in the carboy once the transfer is done. A 6.5g carboy filled at STP holds the better part of a cubic foot of CO2; ending up with higher pressure when the transfer has finished = more lost CO2...

 

[schematix]

Even with a hose clamp around it?

That actually makes it worse. Ring style hose clamps deform the cap and lead to an air leak.

 

[day_trippr]

Ime that's not true at all...

Cheers!

 

[Sbe2]

Here is my setup. I have about 1psi on the keg.

Another option if you are willing to wait would be to add CBC-1 to the keg along with priming sugar. In theory you will naturally carbonated the keg while scavenging the remaining oxygen. Downside is that it may take two weeks.

 

[h22lude]

Here is my setup. I have about 1psi on the keg.

Another option if you are willing to wait would be to add CBC-1 to the keg along with priming sugar. In theory you will naturally carbonated the keg while scavenging the remaining oxygen. Downside is that it may take two weeks.

Unless the beer has been aged awhile, I'd think cbc can be skipped. There should be enough yeast to keg carb.

 

[Sbe2]

Unless the beer has been aged awhile, I'd think cbc can be skipped. There should be enough yeast to keg carb.

I agree, I haven't done it, but it is an option for those who are super anal about oxygen exposure.

 

[h22lude]

I agree, I haven't done it, but it is an option for those who are super anal about oxygen exposure.

I'm starting to get into low oxygen brewing and plan on just dumping sugar into primary a day before kegging. That should be good enough to scanvenge oxygen but having cbc on hand isn't a bad idea. Cheap enough too

 

[schematix]

A day is too long... if it just reached FG it’ll take off within tens of minutes.

 

[h22lude]

A day is too long... if it just reached FG it’ll take off within tens of minutes.

I'm going to try and dry hop for a day and the keg. Should I add the hops the day before and then add the sugar the next morning and transfer that same day? I also want the refermentation to scrub any O2 from dry hopping.

 

[schematix]

I'm going to try and dry hop for a day and the keg. Should I add the hops the day before and then add the sugar the next morning and transfer that same day? I also want the refermentation to scrub any O2 from dry hopping.

Add the hops when you have a few gravity points left... e.g. 1.020. That way you get scrubbing when you add the dry hops. After it hits FG, add the sugar, wait about an hour (yeast love simple sugars and will immediate pounce on them), then rack to the keg and seal it.

 

[h22lude]

Add the hops when you have a few gravity points left... e.g. 1.020. That way you get scrubbing when you add the dry hops. After it hits FG, add the sugar, wait about an hour (yeast love simple sugars and will immediate pounce on them), then rack to the keg and seal it.

That sounds like a plan to me. How much sugar should I add? The same amount I would in the keg for naturally carbing? Do you ever use CBC-1?

Just out of curiosity, how do you take gravity readings without introducing O2? Do you have a spigot?

 

[schematix]

Never heard of CBC-1.

I add as much as is needed to fully carbonate (aim low though if in doubt). The one i did the other day i mixed 100g of dextrose into 200g of RO water, which gave me about 250mL of solution. I used 200mL of that for 10G. Seems to be right about on target.

I ferment in a corny keg under slight pressure so i just attach a cobra tap to the liquid port and pull a quick sample.

 

[popquizkid]

Add the hops when you have a few gravity points left... e.g. 1.020. That way you get scrubbing when you add the dry hops. After it hits FG, add the sugar, wait about an hour (yeast love simple sugars and will immediate pounce on them), then rack to the keg and seal it.

I agree with this. I have been using this transfer technique for a while now and after about an hour or two of adding the priming sugar there is visible activity within the fermentor. It doesn't take very long for the yeast to get working on priming solution.

 

[h22lude]

Never heard of CBC-1.

I add as much as is needed to fully carbonate (aim low though if in doubt). The one i did the other day i mixed 100g of dextrose into 200g of RO water, which gave me about 250mL of solution. I used 200mL of that for 10G. Seems to be right about on target.

I ferment in a corny keg under slight pressure so i just attach a cobra tap to the liquid port and pull a quick sample.

It's a very neutral flavored carbing yeast. Most batches probably won't need it since there will be enough healthy yeast to eat the added sugar.

Perfect, that's what I assumed. I've never naturally carbed kegs but like the idea for oxygen scavenging.

Oh that's a good idea. I've been looking at the ss brew bucket but keep reading about using corny with spunding valve. I'll have to look more into it.

 

[schematix]

Oh that's a good idea. I've been looking at the ss brew bucket but keep reading about using corny with spunding valve. I'll have to look more into it.

I don't think corny kegs make the ideal fermenter, BUT, they can do a lot and are super cheap.

IMHO a conical with a sampling port and rotatable racking arm is the best way to go. Only reason i haven't gone down that route yet is I'm still on the fence about buying something like 3x SS Brew Buckets, or 1x 20G glycol jacketed conical.

 

[h22lude]

I don't think corny kegs make the ideal fermenter, BUT, they can do a lot and are super cheap.

IMHO a conical with a sampling port and rotatable racking arm is the best way to go. Only reason i haven't gone down that route yet is I'm still on the fence about buying something like 3x SS Brew Buckets, or 1x 20G glycol jacketed conical.

I keep eyeing the brew bucket but was then reading about using a corny. Since I have more kegs than taps, I already have empty ones. But I do like the rotating racking arm with sampling port and the beer can be transferred with some co2 from the port in the lid. I will probably still go that route.

 

[Nav71292]

They are the gas pressure equivalent of electrical fuses.

I'm clearly a bit whack but not completely crazy I put those in the system to preclude the biggest bottle grenade ever from happening in case something goes wrong.

Dry tested a couple of samples of that particular balloon type (a couple dozen in the bag for a couple of bucks) with the carboy covered in welding blankets and blew 'em up. It was actually pretty exciting the first time

[edit/added]


Yes, I believe I had just kicked off the crash on those batches.
I set the gas so the low pressure needle moves off the stop and that's about it.

That's a fairly hefty stainless steel washer that keeps the nylon mesh from getting sucked up the dip tube, and maintains a pretty good envelope in the mesh so it doesn't clog up. I have a tape marking the dip tube level that keeps the tube above the typical trub/hop pile at the bottom, with the washer dangling below - or usually, resting on top of the pile.

It works pretty well, worst case I end up with a few tablespoons of detritus coating the keg bottom when it kicks...

Cheers!

Hi! Tremendously helpful thread here. I did my first closed transfer but didn't use the screen on the end of the racking cane, so my QDs got plugged up with hops several times and it was a bit of a nightmare.
Do you keep the little cap/reservoir on the bottom end of the racking cane with your washer technique? I almost feel like with that cap on there, it may be best to keep the screen/mesh taut and then zip tie it or something further up the racking cane. Maybe not?

 

[day_trippr]

If you take a look at post #5 you'll see exactly what equipment I use, but it's just a simple one piece stainless racking cane in the carboy with the nylon mesh and ss washer rubber-banded thereto and sanitized well. There's nothing else involved at that end...

Cheers!

 

[Nav71292]

Got it! Thank you

If you take a look at post #5 you'll see exactly what equipment I use, but it's just a simple one piece stainless racking cane in the carboy with the nylon mesh and ss washer rubber-banded thereto and sanitized well. There's nothing else involved at that end...

Cheers!

 

[Nebraskan]

After fermentation I chill, then gelatin fine, wait 24 hours and then filter through 5 micron under CO2 pressure from my Mini Brew 6.5 gallon connical (by Hobby Beverage) through the 5 micron filter setup I concocted, and then into a CO2 gassed keg. Comes out sparkling clean before I pressure the keg. I use a paint ball tank of 24 oz and an adapter for my CO2 valves and gauges and control the pressure to low 2-4 lbs of pressure. Beer is constant under CO2, the pressure is what forces the beer slowly (this is the KEY) through the 5 micron filter and into the keg.

 

[schematix]

I don't quite think that qualifies as a closed system with the serving keg lid wide open

 

[Nebraskan]

I could have gone thought the OUT beer side, but that become problematic to know when it is at the full level you want, and with the vent open over fills the kegs or spills beer. The CO2 in the keg raised and poured out as the beer was filling from the bottom. Primary "was" completely closed during the whole exercise.

 

[day_trippr]

I solved the closed filling problem with a scale, if I'm going to run over 5 gallons I put the excess in a carbonator bottle.
Fortunately BS2 usually gets the "to the fermentor" volume dead nuts on, but I still use the scale...

Cheers!

 

[Brewfish51]

So, going back to the very first part of this conversation and the carboy to Corny keg transfer using CO2: I see the pics with beer going into the Corny via a black (out) keg post, and I’m seeing a few people calling it a “liquid in” post. I tried this transfer, and the beer would not pass through the black keg post.
Yes, it was all the way clicked onto the keg. I checked.
The black “out” post I used was the threaded version. Should I have used the barbed version? I see that those are referred to as “liquid” keg posts, but will liquid flow backwards through them?
I know this is a very basic question, and I know I could set it up and try it without the embarrassment of asking, but I’m pretty frustrated, and I just want someone to tell me it’ll work.
I looked at day tripper’s pics, which are great, but fuzzy when I zoom in.
Thanks for the help..

 

[volsherdeers]

So, going back to the very first part of this conversation and the carboy to Corny keg transfer using CO2: I see the pics with beer going into the Corny via a black (out) keg post, and I’m seeing a few people calling it a “liquid in” post. I tried this transfer, and the beer would not pass through the black keg post.
Yes, it was all the way clicked onto the keg. I checked.
The black “out” post I used was the threaded version. Should I have used the barbed version? I see that those are referred to as “liquid” keg posts, but will liquid flow backwards through them?
I know this is a very basic question, and I know I could set it up and try it without the embarrassment of asking, but I’m pretty frustrated, and I just want someone to tell me it’ll work.
I looked at day tripper’s pics, which are great, but fuzzy when I zoom in.
Thanks for the help..

Are you venting the keg so it doesn't build pressure ? is the beer clean, meaning does it have particles in solution that may be clogging the fitting ! I just use a gas connecter to vent the keg while filling! I put it on just before I start the transfer.

 

[4of7]

Closed transfer.primary 50 liter to 5corny

 

[4of7]

After fermentation I chill, then gelatin fine, wait 24 hours and then filter through 5 micron under CO2 pressure from my Mini Brew 6.5 gallon connical (by Hobby Beverage) through the 5 micron filter setup I concocted, and then into a CO2 gassed keg. Comes out sparkling clean before I pressure the keg. I use a paint ball tank of 24 oz and an adapter for my CO2 valves and gauges and control the pressure to low 2-4 lbs of pressure. Beer is constant under CO2, the pressure is what forces the beer slowly (this is the KEY) through the 5 micron filter and into the keg.

View attachment 570809

View attachment 570810

View attachment 570811

Put the lid on.purge keg.transfer to liquid in .pull gas open every couple times.your good I try the filter.did not like it.

 

[Unicorn_Platypus]

I do closed xfers using the orange cap and ss racking cane setup

I switched to PET plastic carboys from glass and couldn't be happier with the results.

The vintage shop brand PET Carboys are graded to 10 psi (I emailed the manufacturer)

Agree that the risk of breaking glass is low, but man these plastic ones are much easier to deal with in general. I've noticed absolutely no difference in beer quality between plastic and glass.

 

[Brewfish51]

Are you venting the keg so it doesn't build pressure ? is the beer clean, meaning does it have particles in solution that may be clogging the fitting ! I just use a gas connecter to vent the keg while filling! I put it on just before I start the transfer.

Yes, I popped the keg vent and turned it 90 degrees so it would vent, but the beer would not flow. It was clearly not making it past the black keg post on the 'out' side. Beer ran clear, no particles, all the way to where it stopped. I even ended up popping the lid off the keg, still no flow.

 

[ajdelange]

So, going back to the very first part of this conversation and the carboy to Corny keg transfer using CO2: I see the pics with beer going into the Corny via a black (out) keg post, and I’m seeing a few people calling it a “liquid in” post. I tried this transfer, and the beer would not pass through the black keg post.

Functionally all the posts are the same be they pin lock, ball lock, liquid, gas, barbed or flare hose connection. They are simple enough to check and, if they won't pass liquid, disassemble and clean. However there are two types of ball lock and you must have the correct 'connector' for them to work. Again, this is pretty easy to test. Remove the fitting from the keg (a socket wrench works though for the pin type you must buy a special socket with slots for the pins or make one yourself by grinding those slots) and push the connector on. If it's the right connector it snaps on easily and fluid will flow. If it doesn't feel right going on you probably have the wrong connector though you can disassemble post and connector to check that they are clear of gunk.

I finally got so fed up with never being able to locate the right connector that I gave up and went to Sankey. I've never looked back.

 

[IslandLizard]

The black “out” post I used was the threaded version. Should I have used the barbed version? I see that those are referred to as “liquid” keg posts, but will liquid flow backwards through them?

How did you connect the racking hose to the threaded quick disconnect (QD)? If you just clamped the hose over it, chances are you lost the siphon/prime. You cannot seal a vinyl hose over threads, it will leak (air), thus losing prime.

Also, both the QD poppet and the keg's post poppet are spring loaded. When you connect the QD, both springs need to compress enough at the same time in order to create a passage.

Unless the QD contains a check valve (some pinlock QDs have those built in) there is no directional restriction. Liquid and gas will flow either way.