Random question-purging air from keg

[htims05]

I’m going to store a keg for a while empty. I read that cleaning it, let it dry and then seal it up with CO2 is a decent plan.

My question is, about how many burps of the purge valve should be enough to get all the air out so the keg is all co2 and at what pressure should I store it?

 

[Dgallo]

I’m going to store a keg for a while empty. I read that cleaning it, let it dry and then seal it up with CO2 is a decent plan.

My question is, about how many burps of the purge valve should be enough to get all the air out so the keg is all co2 and at what pressure should I store it?

How do you rack into the keg when you fill your beer? Closed transfer or open the top?

 

[htims05]

How do you rack into the keg when you fill your beer? Closed transfer or open the top?

Typically open the top since I sanitize right before adding the beer.

 

[Dgallo]

Typically open the top since I sanitize right before adding the beer.

If your going to open the lid and sanitize right before you keg next time anyway, I’m having a hard time understanding why you would need to purge it before storing it. You certainly could do it if you chose but I don’t see what benefit it would bring. Maybe someone will chime in that knows the reasoning behind it

 

[ScrewyBrewer]

I've been filling cleaned kegs with StarSan solution and 30 psi Co2 before storing them away. The next time I need one they're all ready to go.

 

[govner1]

I clean my kegs with B-Brite then rinse with hot water, then put in about 1/2g of StarSan and shake the keg to sanitize before emptying StarSan then put on lid with no pressure and store.
I was taught early on that storing under high pressure weakens the poppet spring.
Don’t forget to take apart you ball lock posts and clean as well.

 

[Robert65]

To eliminate all air from a keg by burping the PRV requires that it be fully pressurized to 30 psi, then fully depressurized by pulling the PRV, for 16 full cycles. That is a truly enormous amount of CO2 to waste, not to mention time. At 20 psi, you would need to do at least 21 full cycles. The only practical way to purge a keg is to fill it completely with liquid, and push all the liquid out with CO2. Since you need to sanitize anyway, fill it with sanitizer and push that out. Then the exact pressure is irrelevant, just as much as you need to push out the liquid, and seat the lid. Then you are ready to do a closed transfer, or to store the keg if you want. Storing a keg with any amount of pressure at all will allow you to confirm that it is holding pressure when you are ready to use it. If not, you know you need to track down a slow leak and fix it.

 

[htims05]

If your going to open the lid and sanitize right before you keg next time anyway, I’m having a hard time understanding why you would need to purge it before storing it. You certainly could do it if you chose but I don’t see what benefit it would bring. Maybe someone will chime in that knows the reasoning behind it

I'm making the assumption (maybe incorrectly) that air has a bunch of impurities and may have contaminates that over time wouldn't be nice to leave inside trapped...for things to grow/eat. But if it only had CO2 that would be less likely to have villains in there over time.

I don't know - I read all the comments from leave it completely full with water, to store upside down but open (or not since bugs then get in there), to just a bit of star san left in it, but sealed and no pressure as that'll ruin the seals/poppets, to keep pressure on it so you know if the seals are bad when you go to use it again.

Sounds to me that there's no wrong way to store a keg, no right way either. Over thinking this I presume.

 

[Robert65]

The simple solution is to store it any old way you like as long as it is cleaned first, then sanitize and purge immediately before filling with beer.

 

[htims05]

The simple solution is to store it any old way you like as long as it is cleaned first, then sanitize and purge immediately before filling with beer.

Yep I think after reading all the opinions this is what I'm going to do...clean them, dry, seal up with say 10psi.

I'd most likely clean and sanitize again when I go to fill them anyway - especially if its been siting for months.

 

[htims05]

To eliminate all air from a keg by burping the PRV requires that it be fully pressurized to 30 psi, then fully depressurized by pulling the PRV, for 16 full cycles. That is a truly enormous amount of CO2 to waste, not to mention time. At 20 psi, you would need to do at least 21 full cycles.

Crap - ok not doing that.

 

[Vale71]

The only difference between a purged keg and a keg full of air would be the availability of oxygen, but since some very nasty critters actually thrive in an oxygen-free environment that won't really offer much protection per se.
One thing no life on Earth can do without though is water, so if you let your keg dry completely before closing it up it won't matter what gas mixture is inside, you're guaranteed that nothing will be able to reproduce in there even if you store the keg for hundreds of years before using it again.

 

[Drumminguy81]

Personally I clean, sanitize, then put the lid on and fill with co2. I leave the prv open for... I donno 4 seconds.. then close and pressurize to 20ish psi. I closed transfer so less co2 is wasted. Co2 is heavier than air so air should be pushed out the spunding valve as i push the beer in only leaving the co2. So far no issues. I prefer to store my kegs pressurized because 1, it's easier to see if I have a leak, 2, less chance of contaminants getting in. Occasionally I have kegs sit for many months unused. I have 20+ kegs though.

 

[TurnipGreen]

I’m pretty new to kegging so take this for what’s it’s worth. I also do open transfers.

I clean the kegs and the fill the with star sans. Leave the star sans in there. Purge out the air and the I just add enough pressure to keep it sealed. All I re-sanitized at packaging time is the lid.

It’s been working for me.

 

[Robert65]

Co2 is heavier than air so air should be pushed out the spunding valve as i push the beer in only leaving the co2.

The CO2 "blanket" line of thinking in homebrew circles is a particularly difficult myth to dispel, it seems. It doesn't work like that in our universe, given the pesky laws of physics and chemistry we are stuck with. Gases don't stratify, they mix, and very nearly instananeously, by diffusuion. If you want to avoid contact between beer and air, the air must be completely eliminated, and as mentioned earlier, the only practical way to do this is by liquid-purging the keg. Pulling the PRV a few times has exactly zero benefit.

 

[Rikk]

Gases don't stratify, they mix, and very nearly instananeously, by diffusuion.

Case in point “Beer Gas”. 70/30 is a mix of nitro and co2. You don’t get all the co2 before the nitro.