Best Way to Get Sanitizing Solution Out of Keg Full of CO2?

[Clint Yeastwood]

Now that I'm a big closed-transfer, pressure-brew expert, I need to get a handle on preparing serving kegs.

I have been keeping a keg full of Star San solution, and I pump the solution into another keg. Then I use the first keg for serving.

Getting all the solution out without letting oxygen in is kind of a job. The PRV is not a great solution because when you invert a keg, the solution level in the lid is lower than the height of the PRV intake.

What do the rest of you do? I'm using Torpedoes, ball lock Cornys ("Cornies"?) and converted pin lock Cornys which I decided to retrofit with ball lock lids.

I was thinking I might start removing one keg post and letting the solution blow out under pressure. I ought to be able to get the post back on while CO2 is still blowing out. I don't want to start thinking about how much O2 goes in when CO2 is blowing out. I would prefer to pretend it doesn't happen.

I bought myself some Flotits, and I figured I would also try the little Uni gas tubes. I could not figure out how they were an improvement on regular tubes, but I decided to take a chance on the Flotit guy being smarter than me, and I bought them anyway. They are short, so they should let just about all the solution out.

I suppose an ounce of solution isn't a big deal, but it's fun to think one is doing something right.

 

[IslandLizard]

Simple!
Cut off the gas diptube so it's flush, or even a little shorter, so nothing sticks out below the "bottom" of the dome it sits in.

Invert the mostly purged keg, with some pressure left in it, keeping it under a slant with the gas post at its lowest point. Then push in the gas poppet or stick a QD on it. That should purge the last of the sanitizer.

I doubt there is more than an oz (or 2) of liquid/sanitizer left by just regular "upright" vertical purging, unless you shortened the liquid dip tube.

 

[Clint Yeastwood]

That makes perfect sense. Better than fiddling with a keg post. Thanks.

 

[day_trippr]

I doubt there is more than an oz (or 2) of liquid/sanitizer left by just regular "upright" vertical purging, unless you shortened the liquid dip tube.

In fact, with a full length dip tube properly positioned in its keg bottom well, one can leave less than a teaspoon of liquid behind...

Cheers!

 

[Clint Yeastwood]

I have a wheat blerping away into a jar of BTF and water, and I will consider all this advice while kegging it in a day or two.

 

[mashdar]

If keg is ready when fermenting, you might consider using the fermentation gas to purge the keg.

I just accept there's a touch of star san (like day_trippr said, it's surprisingly little) in the beer. "Don't fear the foam" and all that.

 

[Bayou Fatma Brewer]

Now that I'm a big closed-transfer, pressure-brew expert, I need to get a handle on preparing serving kegs.

I have been keeping a keg full of Star San solution, and I pump the solution into another keg. Then I use the first keg for serving.

Getting all the solution out without letting oxygen in is kind of a job. The PRV is not a great solution because when you invert a keg, the solution level in the lid is lower than the height of the PRV intake.

What do the rest of you do? I'm using Torpedoes, ball lock Cornys ("Cornies"?) and converted pin lock Cornys which I decided to retrofit with ball lock lids.

I was thinking I might start removing one keg post and letting the solution blow out under pressure. I ought to be able to get the post back on while CO2 is still blowing out. I don't want to start thinking about how much O2 goes in when CO2 is blowing out. I would prefer to pretend it doesn't happen.

I bought myself some Flotits, and I figured I would also try the little Uni gas tubes. I could not figure out how they were an improvement on regular tubes, but I decided to take a chance on the Flotit guy being smarter than me, and I bought them anyway. They are short, so they should let just about all the solution out.

I suppose an ounce of solution isn't a big deal, but it's fun to think one is doing something right.

https://brulosophy.com/2020/04/13/c...eg-with-co2-at-packaging-exbeeriment-results/

 

[Clint Yeastwood]

So he left two serving kegs open to the outside air and filled them by relying on gravity, while releasing CO2 into one fermenter and one keg, but letting outside air into the other vessels. Is that right? Not clear how he got gas into the second fermenter to allow the beer to get out, so I assume he let air go in the top. I am not familiar with his fermenters, but something had to go into the non-purged keg to prevent the pressure from dropping and the beer from getting stuck.

It sounds like a lot of oxygen got to both samples. I'm not sure I understand the experiment. If it were me, I'd compare open to closed instead of open to somewhat less open.

I use CO2 to push beer from fermenters into kegs already full of CO2. I pump gas into the fermenter using a regulator. I put a spunding valve on the gas post of the serving keg to let CO2 out. I keep the push pressure a little higher than the spunding valve pressure. I try to keep some pressure in both kegs so the beer doesn't foam up and so I still have some carbonation in the beer after the transfer. I don't open the system to the outside air. I thought this was the way to do it.

I lose a keg full of CO2 every time.

 

[Bayou Fatma Brewer]

So he left two serving kegs open to the outside air and filled them by relying on gravity, while releasing CO2 into one fermenter and one keg, but letting outside air into the other vessels. Is that right? Not clear how he got gas into the second fermenter to allow the beer to get out, so I assume he let air go in the top. I am not familiar with his fermenters, but something had to go into the non-purged keg to prevent the pressure from dropping and the beer from getting stuck.

It sounds like a lot of oxygen got to both samples. I'm not sure I understand the experiment. If it were me, I'd compare open to closed instead of open to somewhat less open.

I use CO2 to push beer from fermenters into kegs already full of CO2. I pump gas into the fermenter using a regulator. I put a spunding valve on the gas post of the serving keg to let CO2 out. I keep the push pressure a little higher than the spunding valve pressure. I try to keep some pressure in both kegs so the beer doesn't foam up and so I still have some carbonation in the beer after the transfer. I don't open the system to the outside air. I thought this was the way to do it.

I lose a keg full of CO2 every time.

I kinda do the same as you just a lil different. After cold crashing, I put about 3-4 psi co2 on my fermenter and push the beer into the liquid line of a sealed sanitized keg. I leave an open quick connect on the other post to bleed pressure. When the keg is full I pressurize the keg to 25 psi to seal it and pull the prv about 8-10 times hopefully getting rid of any oxygen in the Corny keg. Then I do the set and forget with about 10 psi on the Keg. This always worked well for me without and off flavors that I can detect And don’t lose much co2 this way.

 

[Clint Yeastwood]

I have been moving beer with a lot of carbonation due to pressure fermenting. I have a wheat going now, and I read that pressure kills the esters, so I am using a blowoff tube.

I don't know if it's a good or bad idea to carbonate flat beer before moving it.

 

[mashdar]

You can siphon without wasting CO2 by connecting liquid-liquid and and gas-gas. The CO2 from the serving keg transfers to the fermenting keg, and gravity does the work.

Requires a little pressure management at start. Also best to start with purged lines.

 

[Clint Yeastwood]

When all that's over, you have a dirty fermenting keg full of CO2, so what do you do?

 

[Unicorn_Platypus]

Trong the maker of the flotit actually sells cut stainless steel diptubes if you email him

I picked up a bunch from him and fit to all my kegs

[email protected]

To purge the sanitizer I use a picnic tap with a gas QD, flip the keg upside down and tilt it

I purge the line with CO2 before hooking it up to the keg.

To purge all my hoses I use an assembly like pictured which is basically just two carb caps connected. Makes it super easy to purge jumpers, spunding valves etc before connecting

 

[Clint Yeastwood]

I got a couple of his Uni tubes out of curiosity. Very short, but they really do not like to come out of the keg posts after they're used.

 

[Unicorn_Platypus]

I got a couple of his Uni tubes out of curiosity. Very short, but they really do not like to come out of the keg posts after they're used.

The only reason I don't like the untubes is that they are silicone. Silicone is highly permeable to O2.

The cut dip tubes he sells are stainless steel with EPDM O rings.

I've also gotten rid of all silicone O rings on my kegs (especially the large one for the lid) and replaced with EPDM.

Generally Buna N & EPDM offer good barrier. Kegland just made some new ones called low2. I think they are made of EPDM and some other materials

 

[Clint Yeastwood]

I thought about the O2 problem AFTER I installed the tubes. Right now, all my big O-rings look like buna.

I am not sure why a gas tube ever needs to be long. I don't see why I shouldn't cut mine short.

 

[Unicorn_Platypus]

The only reason for them to be long is to prevent overfilling

If you fill a keg to the brim with cold beer and it warms up the liquid will expand

Now kegs do have PRVs, so generally would mean liquid would pour out the PRV rather than exploding your keg. Still good practice not to overfill and leave about 30oz of headspace

If you are confident your beer is going to stay cold and in a keezer its not a huge concern though

However you can be careful not to overfill with short gas diptubes too.

I use a digital medical scale when filling all my kegs so can cap it off when it gets to the right level. You could also fill to the brim and pour off a pint or two.

 

[Clint Yeastwood]

I took a look, and it appears most of my gas tubes are really short already.

I always thought headspace was for carbonation, but then I slept behind a dumpster last night because the Holiday Inn Express was full.

 

[Clint Yeastwood]

Still hoping for an answer to this one.

When all that's over, you have a dirty fermenting keg full of CO2, so what do you do?

 

[Broken Crow]

Still hoping for an answer to this one.

If you haven't dry-hopped in it and you have confidence in your sanitation process, you can dump another batch in it to re-use the yeast, or you open it up to clean it and lose the CO2. Sooner or later we have to lose CO2 to cleaning/sanitizing/purging.
As to the gas diptubes, I really should cut mine short and flush, but I like that the manufacturers (at least of traditional corny's) have the diptube length such that their bottom is exactly flush with 5-gallons. It shouldn't matter to me because I fill on a scale, but I kinda like when I see a bit of foam start coming out the gas return-line just before I've hit my volume. I don't have the space or ergonomics anyway, to tilt a keg full of Star San and get rid of all the air, so I install the lid while Star San runs freely out around it, and then connect CO2 to the liquid tube to maximize bubbling and purge through the PRV. My theaory being; the bubbles are entirely full of CO2 and their membranes will push that last bit of O2 down and out the PRV stem. It's messy and not as good as a shortened gas diptube, but it's more ergonomic for me and I haven't had any oxidation or infections.

 

[Unicorn_Platypus]

If you haven't dry-hopped in it and you have confidence in your sanitation process, you can dump another batch in it to re-use the yeast, or you open it up to clean it and lose the CO2. Sooner or later we have to lose CO2 to cleaning/sanitizing/purging.
As to the gas diptubes, I really should cut mine short and flush, but I like that the manufacturers (at least of traditional corny's) have the diptube length such that their bottom is exactly flush with 5-gallons. It shouldn't matter to me because I fill on a scale, but I kinda like when I see a bit of foam start coming out the gas return-line just before I've hit my volume. I don't have the space or ergonomics anyway, to tilt a keg full of Star San and get rid of all the air, so I install the lid while Star San runs freely out around it, and then connect CO2 to the liquid tube to maximize bubbling and purge through the PRV. My theaory being; the bubbles are entirely full of CO2 and their membranes will push that last bit of O2 down and out the PRV stem. It's messy and not as good as a shortened gas diptube, but it's more ergonomic for me and I haven't had any oxidation or infections.

The problem with the PRV is it isn't flush to the lid. There's a few ounces that get trapped in the lid

 

[mashdar]

I guess if you truly wanted to go nuts, you could bleed the gas-in post by loosening the post fitting. While holding the keg upside down. That would bypass the dip tube.

 

[Mac's Brew]

Clint, do NOT overthink this. Like you, I also use Cornelius kegs and Torpedo kegs. I brew 1 bbl batches and pressure transfer to kegs.

The design of the Cornelius kegs is such that very little sanitizer is left behind when purged - the dip tube goes into the dimple in the concave bottom of the keg, leaving less than 1/2 oz. of sanitizer in the bottom. That is an irrelevant amount in 640 oz. (5 gal.) of beer. Don't worry about it.

Torpedo kegs are another story. Their design leaves a few ounces of sanitizer after purging. Here is what I do to mitigate this: When the sanitizer level in the keg is getting low, I tip the keg toward the dip tube to get as much sanitizer out as possible. It may leave 2 oz. behind in the keg. That's .3% of 5 gallons, which is insignificant. I don't think you need to worry about that small amount.

I cannot tell the difference between the beer dispensed from a Cornelius keg vs. that dispensed from a Torpedo keg when I use both type of kegs for a batch. If you're brewing a really delicate beer (e.g., a pilsner), just use a Cornelius keg and your problem is solved. My advice is, don't worry about it. Your beer is going to be ok in either keg. Enjoy your hobby and your beer!

 

[Clint Yeastwood]

Thanks for the help.

I think IslandLizard pretty much ended the problem for me, with a solution that was obvious yet which I did not come up with on my own.

I believe my blindness was caused by the fact that I had some short liquid tubes from floating dip tube assemblies on some of my gas posts. A short liquid tube may be 3" long, so they don't work too good for purging an inverted keg. I am now taking care to make sure my gas post tubes are short. I purged a Corny today while kegging a wheat, and it worked fine.

 

[Peteinno]

Curious as to how much liquid came out when you used the new purge method.

 

[FloppyKnockers]

All these answers are great. I was gonna say tannerite. Should probably go with one of the other answers.

 

[Clint Yeastwood]

Almost nothing came out. I had a Flotit in the keg, and it apparently did a tremendous job.