How often should a keg be disassembled and cleaned?

Question

Right now I give my corny kegs and beer lines a hot rinse, PBW soak, rinse and Starsan in-between batches. I inspect for gunk but don't fully disassemble (posts, etc.) unless there's something obviously wrong. I usually re-lube the lid O-ring to ensure a good fit, but nothing else.

Is there a rule of thumb for how often to completely disassemble and re-lube a keg? Does the lubricant degrade? Are there places I can't see where gunk builds up that I should check more frequently?

(This is curiosity only. I'm not currently having any problems.)

Answer 1

I know a lot of people that are in the same boat as you, only cleaning them thoroughly every several batches without issue. I personally disassemble my kegs every time, giving them a good oxi-clean/PBW soak, using my carboy cleaner to ensure it gets a good thorough scrub. I use a brush to get into the dip tube, soak the posts, and then do a thorough rinse and let it soak with Star San for a bit while I hit every bit of rubber from the gaskets inside the posts to the lid with lube. A tube of that lube will last the average homebrewer a lifetime, so there's no need to be conservative with it. The posts, connectors, and taps are likely the places where if there is any build-up, that's where it will be. Unless you're moving your kegs around a lot, they will remain settled , therefor likely never touching the lid or anything at the top of the keg past the initial fill-line (plus whatever minimal displacement from CO₂ with carbonation). When doing a quick cleaning, you should run some no-rinse sanitizer under pressure through the keg if you don't want to remove the posts/hoses/taps, to ensure everything is flushed out.

It sounds like you're fine in your methods, by your lack of issues. The only recommendation I have is when you do your soaks, attach a CO2 connector to the out-post (just the connector, nothing attached to it which would close it off), as it is likely that the closed-off post may not allow for the PBW/Sanitizer solution to get up into the dip tube (think of holding a cup upside down and pushing it into water, no liquid will get into the cup as long as it's upside down). Having the connector on the post will allow for your cleaning/sanitization solution to get up into the dip tube.

Finally, a word of caution, make sure to keep all your posts, gaskets, every bit and piece with the keg that it came from. If you are cleaning multiple kegs at the same time, do not mix and match posts, lids, the little stem that acts as a gasket inside of the CO₂-in post, or anything like that. From experience, some time ago I purchased a keg, and along side it cleaned two others. One of them has a bad dented post that leaks terribly, I mixed and matched the parts out of recklessness, and now I have a mess of parts that either aren't threaded to fit properly, or the inner stem doesn't fit correctly in all kegs, etc...

Answer 2

If all you are using the keg for is dispensing, and the keg is not sitting somewhere room temp for a while in-between filling, what you are doing will most likely not impact you negatively. Leaving the keg with only a rinse style cleaning at room temperature is asking for bacterial growth.

The poppets in the posts tend to build up gunk in the springs that can be difficult to clean simply by the beer sitting on them. The o-rings, poppets, and pressure relief valve will get some beer under/between them and you cannot guarantee that proper cleaning or sanitation occurred. You should also use a brush to clean the dip tube. I would not consider a keg that was not fully disassembled to be sanitized. Therefore, if you are also using your kegs as secondaries, I'd make sure to disassemble them when cleaning and sanitizing.

Your dispensing equipment should ALWAYS be cleaned via disassembly and brush, especially because of the plastic bits. There is no way to assure a proper cleaning without doing this. I'm sure you have been to bars where the tap beers, especially the rotating ones, have an off-taste - this is because they do not properly clean and brush the dispensing equipment when they change to a different keg.

I'd also suggest replacing the o-rings when you do disassemble them. Folks have a tendency to overtighten the posts, pinching them, thus making the o-rings unreusable. The lid o-rings, unless pinched by not paying attention, rarely need replaced. The o-rings, purchased in bulk, are quite inexpensive from an industrial supplier like McMaster:

DipTube: ID 5/16", OD 1/2" (AS568A Dash Number 109) McMaster 9452K172 Buna-N $2.21 per 100.

Post: ID 7/16", OD 5/8" (AS568A Dash Number 111) McMaster 9452K23 Buna-N $2.48 per 100.

Lid: ID 3 1/2", OD 4" (AS568A Dash Number 417) McMaster 9452K218 Buna-N $12.69 per 10.

If you have a restaurant supply store in your area, I'd suggest getting a food grade silicone spray or squeeze tube - it doesn't take much of either to make a good seal and is generally cheaper than at the online stores when you figure shipping in. You should re-lube every time you loosen a fitting with an o-ring.