Cleaning green gunk off a copper immersion chiller

The chiller has been in a bucket in the garage unused for 4 years. I started brewing again so after cleaning off the old equipment I noticed bad oxidization(?) on the copper. Greenish white gunk and some black. I gave it a Star San bath and that seemed to help, then after some scrubbing most of the green is gone (some keeps coming back as it dries but not much). Is it normal to have a good amount of discoloration on this thing? I'd hate to go out and have to buy another one, but I'd hate even more to use it and end up with a metallic tasting beer. Thanks

I haven't had to clean my chiller yet.. but I do have plenty of other copper items I'm the kitchen. From what I understand the green/black is a result of oxidation, copper oxide. That's the part that may lend itself to off flavors and and is not something you want to ingest in moderate concentrations.

I've had good luck using lemon or vinegar and salt. if I have a squeezed out lemon I usually coat it with kosher salt and use that almost as a scrub pad. Sounds like you may have to put some elbow grease into it too.

Is there any pitting or cracks from corrosion??

Check out what John Palmer has to say about cleaning immersion chillers in his book how to brew. http://www.howtobrew.com/appendices/appendixB.html Basically he says to soak it in a vinegar solution.

star san works for me

redm18 said:

Check out what John Palmer has to say about cleaning immersion chillers in his book how to brew. http://www.howtobrew.com/appendices/appendixB.html Basically he says to soak it in a vinegar solution.

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I'll try that as well. This may work for a lightly oxidized piece but this thing had it caked on.

certaut said:

star san works for me

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It worked OK but I bet you didn't have 4 years worth on yours

muriatic acid will make a quick job of it and leave the copper a salmon color.
if it is pitted and the pits are still corroded IMO replace it
pete