initial cleaning of a keggle

[RickWG]

I recently had holes drilled, couplings welded, in a couple of old kegs I ended up with. The stainless guy said I should wash the inside of the keg with acid to "seal the stainless" has anyone heard of this?

Of course I'm gonna wash it out as it had nasty stale beer in it for a while before I got the work done but with acid?

 

[Spyk'd]

I'd give it a good hot PBW soak overnight to rid yourself of the old organic matter in the keg.


About the acid. Yes. To passivate the SS, acid is commonly used. We use phosphoric acid at work (brewery) to passivate our tanks, however, it may be unecessary for the homebrewer. Palmer states that in a couple weeks time, the SS will passivate itself if left clean and unblemished.


You may be worried over nothing.



Of course, if you have rust, that a whole nuther story!

 

[RickWG]

Thanks for your reply,
He did suggest using Phosphoric acid. Don't have any and he said that Muriatic would do. I'll look for phosphoric. I work in a chemistry dept and should be able to dig some up.

No rust just stale beer residue on the inside. PBW it is then.
Thanks for your help.

BTW, what is passivate?

(I'm looking it up now but ....)

 

[WBC]

http://www.dynachrome.com/passivate.htm

http://www.howtobrew.com/appendices/appendixB-1.html

 

[beeraggie]

Passivation is a must. I work in the dairy industry and have seen first hand what happens if you do not. Just soak it in acid for about 2 hrs @ 130 degrees and rinse. Then you need to air it out for 48 hrs before use

 

[beeraggie]

BTW passivation is the removimg of the outer layer on the stainless and allowing all the internal pores close.

 

[WBC]

Passivation is a must. I work in the dairy industry and have seen first hand what happens if you do not. Just soak it in acid for about 2 hrs @ 130 degrees and rinse. Then you need to air it out for 48 hrs before use

Palmer says a good cleaning and then letting it sit 2 weeks takes care of passivation.


John Palmer:
"To passivate stainless steel at home without using a nitric acid bath, you need to clean the surface of all dirt, oils and oxides. The best way to do this is to use an oxalic acid based cleanser like those mentioned above, and a non-metallic green scrubby pad. Don't use steel wool, or any metal pad, even stainless steel, because this will actually promote rust. Scour the surface thoroughly and then rinse and dry it with a towel. Leave it alone for a week or two and it will re-passivate itself. You should not have to do this procedure more than once, but it can be repeated as often as necessary."

Ref: http://www.howtobrew.com/appendices/appendixB-1.html

 

[RickWG]

yeah, I just saw that palmer article. I'm going to get some oxalic acid cleaner tomorrow. If I can get some phosphoric I'll do it that way but may just let it sit for a while to get it done. Since I don't have all the parts for the all grain system yet waiting might be better. Gotta clean it though. old beer schmutz in the bottom.

Thanks all for your replies. I'll try to keep the board informed.

 

[beeraggie]

Palmer says a good cleaning and then letting it sit 2 weeks takes care of passivation.

Granted the longer you can let it sit the better, but we usually can't wait 2 weeks to let a $500,000 tank sit. Anyways, hit with acid and let it air out a while and you will be good to go. If it is a used Keg from a brewery then it was already passivated, just hit any parts that you welded on this is were you really need it.