Kegs And Chemicals

[Snow]

Guys,

would it be a problem if I left an orthophosphoric acid solution in a SS Cornie keg for a few weeks, or would it pit the SS?

On a similar note, could I do the same with caustic beer line cleaner?

Cheers - Snow.

 

[Hoops]

Snow

caustic beer line cleaner is fine. EDIT - as long as it's not an aluminium keg! :lol: :lol:
I think phos acid is OK but a couple of weeks is a long time and being acid I would be a bit sceptical.

Hoops

 

[Trough Lolly]

Snow,
I had a look around HBD on O-phosphoric acid - the common theme is that it can damage SS if its used in its pure form. If you dilute it down to appropriate levels, it's ok in the keg. Phosphoric acid under 40% concentration is fine in SS kegs...

One of the HBD posts suggests that O-phosphoric acid (aka "Terminator") has a recommended rate of 1tsp per 2 Litres. If that's true, then 3 tablespoons in a 19L keg should work...

Here's an extract from HBD#1157 of June 93:

Phosphoric Acid (<=40%) No effect on 304 Stainless Steel
Phosphoric Acid (<=40%) Minor effect on 316 Stainless Steel
Phosphoric Acid (<=40%) No effect on 440 Stainless Steel below 120F

Phosphoric Acid (>40%) No effect on 304 Stainless Steel below 120F
Phosphoric Acid (>40%) Minor effect on 316 Stainless Steel
Phosphoric Acid (>40%) Minor effect on 440 Stainless Steel below 120F

Hope this helps,
TL

 

[Snow]

Thanks, Hoops and TL. Even though my OP is quite dilute, I don't think I'll take the chance. I'll just clean it, rinse and drain before storage, then rinse and sanitise before filling with beer.

- Snow.

 

[jgriffin]

Excuse the stupid question, but what are you doing with empty kegs anyway?

 

[Darren]

Hey Snow,
Don't leave any corrosive agent in a keg for a few weeks.
Caustic or acid it will cause corrosion
Best to wash and dry

 

[sosman]

I have left dilute phos acid in kegs for weeks. I haven't checked the surface under a microscope but it is not obvious to me that it has deteriorated.

 

[big d]

for what its worth guys at diluted rates i reckon you would be waiting a life time to see noticable corrosion eg pitting etc.
at work we have ss tanks full of phos and sulphuric acid and it does take along time to see evidence of corrosion.
i can seek advice from the metalurgical guys at work for peace of mind if you want.

cheers
big d

 

[Snow]

Excuse the stupid question, but what are you doing with empty kegs anyway?

It's that scheduling problem I was telling you about! I've finished a keg, but my stout hasn't finished fermenting. I'm new at this kegging game, so it may take me a while to get the timing right. Hosting a party really throws the scheduling out of whack, too!

- Snow