purging kegs

[Gadjobrinus]

Alright, intrigued. day_trippr and others who use a liquid displacement method, something I've never understood - this is very likely a dumb question - but if your diptube doesn't go all the way down, how do you avoid a pool of star-san, let's say, when driving it out with CO2?

 

[day_trippr]

Well that's kinda a key thing. All of my dip tubes are full-length oem and have been carefully "formed" (IBM jargon for "bent" ) so they're solidly in the center of their bottom wells.

I was actually thinking about doing some tests regarding liquid purging techniques. For instance, some folks think pushing sanitizer out the PRV on an up-right keg is sufficient, but if you flip a ball lock lid over and observe where the PRV opening is there's a considerable volume below that wrt the lid surface. Ounces, even.

Otoh, I've consistently observed kicked kegs with mere tablespoons of fluid remaining. Significantly less than ounces. Thus when I purge a keg, I rapidly fill it upright through the open lid with a large bore hose from my Star San bucket, then lid it, flip it over, connect the bucket to the gas post, connect a purge line to the beer post, then flush until the purge line runs totally clear while I'm gently rocking the keg +- ~45° from vertical.

I'm convinced this is the most effective way to purge a keg prior to filling...

Cheers!

 

[Pkrd]

That video would be great if he had filled up multiple jugs and determined how long it took until they wouldn't extinguish the flame.

 

[leesmith]

I believe @schematix on this stuff very much more than I believe the survival doc. However I’d really like to see some experimental data using a ppb sensitive DO meter on some of the keg purging techniques that I see on this and other forums being supported by lots of math and pretty graphs.

I’d like to see...
DO in beer in purged keg using the following techniques

No purge, just gravity fill with minimal splashing then purge the headspace with CO2 half a dozen times
Purge keg a few times then fill closed transfer
Purge keg with a full star San push then fill closed transfer
Purge keg with boiled water push then fill closed transfer

All of the above followed by
Force carbing
Opening top and priming sugar followed by purging head space
Spunding

Then finally don’t forget keg after one week hooked up to CO2 in kegerator

It’s not like I don’t believe math but you know what the say about figures never lie but liars do figure.

So where is the DO measurement to support all this purging math?

This Twitter post from Scott Janish indicates he’s been testing DO:

https://twitter.com/scottjanish/status/939578062353690624?s=21

Maybe he has some insight.

 

[Gadjobrinus]

Well that's kinda a key thing. All of my dip tubes are full-length oem and have been carefully "formed" (IBM jargon for "bent" ) so they're solidly in the center of their bottom wells.

I was actually thinking about doing some tests regarding liquid purging techniques. For instance, some folks think pushing sanitizer out the PRV on an up-right keg is sufficient, but if you flip a ball lock lid over and observe where the PRV opening is there's a considerable volume below that wrt the lid surface. Ounces, even.

Otoh, I've consistently observed kicked kegs with mere tablespoons of fluid remaining. Significantly less than ounces. Thus when I purge a keg, I rapidly fill it upright through the open lid with a large bore hose from my Star San bucket, then lid it, flip it over, connect the bucket to the gas post, connect a purge line to the beer post, then flush until the purge line runs totally clear while I'm gently rocking the keg +- ~45° from vertical.

I'm convinced this is the most effective way to purge a keg prior to filling...

Cheers!

Great, thanks trippr. Gives me something to think on.

 

[eric19312]

This Twitter post from Scott Janish indicates he’s been testing DO:

https://twitter.com/scottjanish/status/939578062353690624?s=21

Maybe he has some insight.

Thanks for pointing me to that blog. My reading for tonight is set! That specific post is very much what I am interested in seeing. Only do it with kegged homebrew so we can get away from p-chem calculations that may or may not take all variables into account.

 

[leesmith]

Thanks for pointing me to that blog. My reading for tonight is set! That specific post is very much what I am interested in seeing. Only do it with kegged homebrew so we can get away from p-chem calculations that may or may not take all variables into account.

Your welcome. His blog is good but not much data on DO levels if I remember right. That twitter post indicates he’s been testing and tested beer from the guy who wrote the LODO blog mentioned.

You may need to contact him...I’m sure on his blog there is a way...in order to get the data your looking for, if he has any at all concerning your particular questions. Just thought it was a good lead for you and could result in some answers.

 

[bleme]

Clearly pros do measure DO at multiple points in their process, especially in packaging. I’m interested in seeing a pro level packaging measurement applied to typical vs advance vs extreme home brew packaging processes. I’m interested in an instrument measurable variable since sensory analysis seems to give results all over the map.

@MiltonHVAC might actually have that capability.

 

[popsicleian]

Otoh, I've consistently observed kicked kegs with mere tablespoons of fluid remaining. Significantly less than ounces. Thus when I purge a keg, I rapidly fill it upright through the open lid with a large bore hose from my Star San bucket, then lid it, flip it over, connect the bucket to the gas post, connect a purge line to the beer post, then flush until the purge line runs totally clear while I'm gently rocking the keg +- ~45° from vertical.

I'm convinced this is the most effective way to purge a keg prior to filling...

Would you consider making a video of this process? I'm sure it's simple, but I'm having the hardest time picturing it/wrapping my head around it.

 

[day_trippr]

Woof. That'd be a first for me I'll see what I can do next time a keg kicks...which shouldn't be long...

Cheers!

 

[ba-brewer]

Otoh, I've consistently observed kicked kegs with mere tablespoons of fluid remaining. Significantly less than ounces. Thus when I purge a keg, I rapidly fill it upright through the open lid with a large bore hose from my Star San bucket, then lid it, flip it over, connect the bucket to the gas post, connect a purge line to the beer post, then flush until the purge line runs totally clear while I'm gently rocking the keg +- ~45° from vertical.

I'm convinced this is the most effective way to purge a keg prior to filling...

Cheers!

If you have less than a tablespoon when kicked why even invert? Does the inverting get you to an amount even less?
​

Does your gas post extend below the coupler or is it flush or inside the coupler?

Do you purge the head space prior to inverting the kegs? If not then you have small amount of O2 still inside the keg.

 

[day_trippr]

- If you don't invert, the air bubbles are in the lid, not the keg bottom, where the long dip tube ends.
- I cut the gas tubes on all 16 kegs down to ~ 1/2". Doesn't change the keg lid vs PRV geometry.
- I think you need to reread what I already wrote...

Cheers!

 

[ba-brewer]

- If you don't invert, the air bubbles are in the lid, not the keg bottom, where the long dip tube ends.
- I cut the gas tubes on all 16 kegs down to ~ 1/2". Doesn't change the keg lid vs PRV geometry.
- I think you need to reread what I already wrote...

Cheers!

Thanks for the rely.

So I reread the post and think I get it now. The section I quoted is just to fill the keg with starsan, I was think it included filling the keg with CO2. When I converted words to pictures in my mind I was picturing the CO2 post as the drain, and the purge line having CO2 connected to push out the starsan.

To paraphase your process,
bucket of starsan higher than keg
Fill keg with lid off from a bucket mostly full then close lid and invert
connect gas post to the bucket of starsan to continue filling with starsan
connect a discharge/drain line to the liquid out post to expel the trapped air
tilt shake move about until no more air exits and only starsan comes out

not said
disconnect hoses
tip upright
connect a discharge tube to liquid out
connect CO2 and expel starsan(leaving less than a tablespoon)


seems like if the gas post is cut back you could invert and possible get out some of the last tablespoon.

 

[nesbit6363]

Alright, intrigued. day_trippr and others who use a liquid displacement method, something I've never understood - this is very likely a dumb question - but if your diptube doesn't go all the way down, how do you avoid a pool of star-san, let's say, when driving it out with CO2?

I have the same question. I want to do a closed transfer on my next beer but my dip tube doesn’t reach the bottom of my keg. It will probably leave around 8 to 12 oz of my StarSan solution at the bottom.

 

[bleme]

I have the same question. I want to do a closed transfer on my next beer but my dip tube doesn’t reach the bottom of my keg. It will probably leave around 8 to 12 oz of my StarSan solution at the bottom.

You can either replace your dip tube with a longer one, or cut your gas tube shorter, flip the keg upside-down, and go out the gas side.

 

[nesbit6363]

You can either replace your dip tube with a longer one, or cut your gas tube shorter, flip the keg upside-down, and go out the gas side.

Sounds like a plan, I’ll probably try to flip it over first. I guess I’ll have to cut my inlet tube like the above post.

 

[popsicleian]

I have the same question. I want to do a closed transfer on my next beer but my dip tube doesn’t reach the bottom of my keg. It will probably leave around 8 to 12 oz of my StarSan solution at the bottom.

You can slip a short length of 1/4” ID tubing over the dip tube to reach the bottom.

 

[juggabrew]

I have the same question. I want to do a closed transfer on my next beer but my dip tube doesn’t reach the bottom of my keg. It will probably leave around 8 to 12 oz of my StarSan solution at the bottom.

I just flip the keg over and pull the pressure relief valve and let all starsan spray out. Maybe 1-2 oz left over after that. Works great for me

 

[doug293cz]

I just flip the keg over and pull the pressure relief valve and let all starsan spray out. Maybe 1-2 oz left over after that. Works great for me

I've actually measured the volume left that way, and it is about 3 fl oz.

Brew on

 

[hezagenius]

I trimmed my gas dip tube super short, maybe 0.5" if that. I set the keg on its side with the gas post at the top and fill it through the liquid post while venting from the gas post into a bucket. When liquid starts coming out of the gas post, stop the flow and invert the keg to free any remaining bubbles in the lid or wherever. The put the keg at a 45 degree angle with the gas post at the peak and start the flow again to purge out any remaining air bubbles. When the liquid flow has no more bubbles, you are good to go.

 

[nesbit6363]

Thanks everyone for the replies. One more quick question at what pressure do purge, probably just enough to push the liquid out right?

 

[day_trippr]

Ideally, yes, just enough to push everything out while minimizing the amount of CO2 used (higher pressure left in the keg = more grams of CO2 used up).

Employ gravity for most of the effort with a gentle CO2-assist...

Cheers!

 

[ba-brewer]

Most of my kegs will leak unless first seated with 20 or 30psi.

How are you folk getting your kegs to not leak with little to no pressure, are you tweaking the clamp to seal better or cherry picking/matching lids and kegs?​

 

[day_trippr]

The only cherry picking I've done was when buying my (16) used kegs, but I must have been lucky that none of them actually require gas pressure to seal tight enough to at least not leak sanitizer when inverted.

fwiw, while I've not needed them, Williams Brewing sells an oversized lid O-ring that should cure most lid/keg sealing issues. Pricey af but might be worth it...

Cheers!

 

[schematix]

Most of my kegs will leak unless first seated with 20 or 30psi.

How are you folk getting your kegs to not leak with little to no pressure, are you tweaking the clamp to seal better or cherry picking/matching lids and kegs?​

lol that's pretty bad. i have a couple that aren't great but nothing that bad. I have swapped some lids around. I numbered my kegs and lids. I have also replaced some poppets. And of course new seals on all of them.

 

[day_trippr]

Keeping lids matched with kegs is definitely important - I mixed up a pair once and immediately ran into issues.
I labeled them all since then so they don't get mixed up again on cleaning days...

Cheers!

 

[ba-brewer]

Some of my kegs are pin locks that were converted to ball locks, I think those are the loosest/leakiest. 12psi only they leak, hit with 30psi they are seated and hold pressure at 12psi serving pressure after. Not exactly sure how that works but I don't have problems with CO2 leaks.

Kegs are numbered but not the lids, might need to see if I can swap some to get a better low pressure seal then number them too. Thanks.

 

[Rev2010]

How are you folk getting your kegs to not leak with little to no pressure, are you tweaking the clamp to seal better or cherry picking/matching lids and kegs?

As long as the lid is tight on its own and with a little keg lube rubbed on the o-ring all is leak free. I had one lid that was loose from day one. The keg they sent me was stamped 2014 (4 years it must've sat closed in a warehouse). It worked fine with some keg lube and first pressurizing with 30psi (which I do anyway to purge headspace) but I never felt quite comfortable with its seal. New o-ring made no difference so I ordered a replacement AEB lid and all is perfect now, nice and tight.


Rev.

 

[pantherburn]

- If you don't invert, the air bubbles are in the lid, not the keg bottom, where the long dip tube ends.
- I cut the gas tubes on all 16 kegs down to ~ 1/2". Doesn't change the keg lid vs PRV geometry.
- I think you need to reread what I already wrote...

Cheers!

Hi day_tripper,

What did you use to cut down your gas tubes? I was hoping to use my tubing cutter but there’s no way it will cut through the stainless.

 

[bleme]

What did you use to cut down your gas tubes?

I used a Sawzall, then filed smooth.

 

[pantherburn]

I used a Sawzall, then filed smooth.

Thanks! I have both(and a vise). I was hoping you had a technique to make a clean cut in one pass!

 

[Homergah]

Hi day_tripper,

What did you use to cut down your gas tubes? I was hoping to use my tubing cutter but there’s no way it will cut through the stainless.

You need a better tubing cutter!

 

[bleme]

Thanks! I have both(and a vise). I was hoping you had a technique to make a clean cut in one pass!

I just used a new blade, cut a notch, oiled it up, then cut straight through.
A pipe cutter would probably be cleaner and just take a few minutes longer.

 

[day_trippr]

Hi day_tripper,
What did you use to cut down your gas tubes? I was hoping to use my tubing cutter but there’s no way it will cut through the stainless.

I carved a t-slot into a pair of soft pine scraps then used my Dremel with a fiber cutoff wheel. Piece o' cake x 16 gas tubes...

I used the cone grinder to clean up the edges...

Cheers!

 

[MikeCo]

For those who have cut gas tubes off with a tubing cutter, do you have any suggestions on gripping or fixturing the "good" end of the tube without collapsing it? I cut one tube that was long enough (2 inches) to grip it at the throw-away end with a pliers. One of the other tubes I have is only about 1-1/4 inch long, and there isn't enough room to do it the same way. This is the first time I've used a tubing cutter, so it's possible I'm missing something.

 

[Robert65]

My trick is a cheat. I came into a bunch of spare liquid tubes. So I clamp down the long (soon to be scrap) end and just use the tubing cutter to nip off a short gas tube at the good end.

Also note that some gas tubes, especially new, aftermarket ones, may be aluminum instead of stainless. These will collapse instead of being cut under the pressure of a tubing cutter. I expect that @day_trippr's method would be successful on them.

 

[MikeCo]

Well, I was able to cut it by taking my time and only increasing the cutter blade depth little by little. Using a needle nose pliers I was able to grip the narrow end sticking out of the cutter. With reduced cutting depth per revolution, I didn't have to grip as tightly as the last one.

 

[Advance]

I was able to cut mine using a tubing cutter clamped in a vise, a plastic drywall screw anchor, and a correct sized screw. Simply place the anchor inside the dip tube and expand by threading in the screw. I used my vise to clamp the gas tube during this operation, but I am sure padded vise grips would suffice. A power driver can now be used to drive the screw, which will turn the gas tube in the cutter. Use just enough cutting pressure to keep the cut tracking in the parting line. Once cut, the anchor is removed buy fixing the gas tube in a vise or vise grips, and unthreading the screw.

 

[Yesfan]

To eliminate the "air bubble" under the lid and in the gas post, could you just open the PRV and put on a gas disconnect with tubing to a bucket. Then fill the keg with star-san until it spills out of those exit points? Then follow through with the co2 purge.

I usually just purge the head space with short bursts of co2. Since I've expanded my taps and I don't drink as much as I used to, that's going to be longer times for a keg to kick. I'm going to do the full liquid (Star-san in my case) purge of my kegs from here on out.

 

[day_trippr]

Take a look at the under-side of the typical ball lock lid. The PRV extends down a fair bit, meaning there'd be a bubble under the lid...

Cheers!