Stains On Base Of Keg

[KGB]

Hey all, I'm in need of some help. A mate had 2 kegs sitting (sealed) with a little beer dregs in them for a month or two and now has a weird brown stain on the bottom. First thoughts were, of course, rust. When you look at the pic it certainly does look like surface rust but in natural light I'm not so sure. He's tried soaking it with pink powder then scrubbing with a sponge attached to the end of his brew spoon.
When I reached the scene, with my mighty stick arms, I was able to reach inside and scratch at it with my fingers - there is absolutely no texture to it as I would expect with any decent rust and if it was just light syrface discoloration/rust I thought it would have come off long before now....?

I'm at a loss - it looks like rust on first inspection but has no texture when you feel it and won't come off with regular scrubbing. At least one of the kegs had a stocking with hops and marbles sitting in it for the time it was empty as well, I'm not sure if that would have any effect.

Any ideas?

 

[raven19]

Almost looks like a tarnish of some kind?

A bit of CLR maybe? Not sure if this will damage/pit the Stainless though?

I would flush with some keg and line cleaner.

And maybe get a brew into it and see if it tastes ok.

 

[raven19]

Just thinking if its not rust, then maybe give it a good clean, then leave it open to air to see if it passivates the stainless steel.

It might be fine as is.

And if it holds pressure, it maybe fine to use as is.

Hope this is of some help.

 

[KGB]

Cheers raven, thats pretty much what I was thinking - hadn't thought of the CLR though.
I figure its not coming off without a fight, its had good soak with some strong pink powder solution and it is very thin (whatever it is). My next move was going to be try a brew in it and see what happens.

 

[katzke]

Cheers raven, thats pretty much what I was thinking - hadn't thought of the CLR though.
I figure its not coming off without a fight, its had good soak with some strong pink powder solution and it is very thin (whatever it is). My next move was going to be try a brew in it and see what happens.

Not sure what the pink stuff is but try PBW from Five Star. Follow directions of mixing with hot/warm water.

What it looks like to me is just a stain. It could even be beer stone if the kegs have been used a long time for beer. I have not had to tackle beer stone yet so no suggestions on that.

Stainless does not rust unless you do something real bad to it. Beer or water will not make it rust just from use.

I would not just put beer in it until you know it is clean. Like you said it sat for some time with old beer in it and now has been open to the world of living things. A film that bugs can live in and nice fresh beer to eat, sounds like a real recipe for an infection to me.

 

[Justin]

I'd give a soak in hot caustic. Be very careful of course. Especially careful if you are going to put the lid on and shake the thing because now you are dealing with a pressurised vessel of hot caustic that may spray if you aren't careful about how you release the pressure.

Breweries use caustic in CIP applications.

Good luck.

 

[boybrewer]

I really wouldn't worry too much about it my keg has that type of staining in it. I to was worried that it was rust. I think it is only discolouration , I have brewed quite a few batches in it and have no off flavours whatsoever from it.


Mike (BB) :icon_cheers:

 

[fcmcg]

I really wouldn't worry too much about it my keg has that type of staining in it. I to was worried that it was rust. I think it is only discolouration , I have brewed quite a few batches in it and have no off flavours whatsoever from it.


Mike (BB) :icon_cheers:

I'd try a product like oxyper,which seems to clean this type of crud off the bottom of my kegs no prob....
Oxyper,from what i understand,has an active cleaniing agent that means no or little scrubbing....
I know you can get it from the G&G ( no affiliation etc) and i'm sure other decent homebrew retailers would have a similar product...
Cheers
Ferg

 

[Pennywise]

All my kegs had those types of stains in them when I first bought them, PBW did the trick no worries. Although one keg did need a bit of a long'ish soak with a bit more concentrated solution.

 

[Fourstar]

I find anything that is caused by beer in the keg comes off with a tsp of nappysan and a full hot kettle worth of boiling water. seal it up and shake like all hell. leave it to do its thing and check it in an hours time.. if it isnt gone, ill eat my words. otherwise its probabaly something non beer related on the bottom of the keg.