Green / Blue marks appearing on brand new copper immersion coil

I build a copper immersion coil recently with grade L copper from the home depot clearance. Last night I tested it by putting it in my new stainless steel pot with boiling water, heat on. I left it there for 15 minutes as if sanitizing in wort then turned off the heat and ran cold tap water through. After I tested it I noticed that this green or blue powder like substance had appeared on the coil in a few places. The majority of it is outside of where there was water contact, but a couple spots on the bottom of the coil exist too. It kind of smudges when I rub it with my finger but doesn't really come off. Bits off the powder like substance do come off on my finger though. I'm not sure what this is and can't seem to find any info on google. I've attached a couple pictures. Does anyone have any experience with this? What is it, is it safe, is it easy to clean? Any info would be appreciated. Thanks.

 

That is verdigris http://en.wikipedia.org/wiki/Verdigris
Not sure why it is occuring, but it is poisonous, so you'll need to take precaution.

 

Soak it in star San it it will be bright copper again.

 

That's kinda crazy looking, put some bar keepers friend on there and she will shine bright like a diamond....lol

Seriously, I use bar keepers on all my copper and stainless, works like a champ..

 

Try star San... no scrubbing required. Ever see ketchup on a copper bar or table top? Same thing.

 

When copper corrodes , think "rust", it turns green. It is why the Statue of Liberty is green. It is poison, so be sure to clean it up.

 

Thanks for the help guys. I looked up some more information on verdigris and it sounds like I shouldn't have anything to worry about assuming I thoroughly clean it. I took some bar keeper's friend to all the spots and they cleaned up immediately. Not sure how this would have happened with brand new copper after just one test with water only though.

A couple links I found for anyone googling about this issue as I couldn't find anything and had no idea what this was called:

http://forum.northernbrewer.com/viewtopic.php?f=1&t=47720

http://www.homebrewtalk.com/f14/verdigris-my-wort-chiller-435305/

http://www.homebrewtalk.com/f11/copper-verdigris-copper-chloride-wort-chiller-354843/

 

Just means your water chemistry is a little acidic. You'll have to clean your chiller more than some.

 

My copper chiller always accumulated this at one point in particular, for no apparent reason - it always went away and came back when exposed to starsan, wort etc...

Eventually, I just took some scotchbrite to it and rubbed it back to completely bare copper and it hasn't been back since.

 

Since this has been revived recently and it's been a little over a year since my original posts let me give a quick update.

I cleaned all the spots with bar keeper's friend and everything was removed very easily. I didn't have to do a deep scrub or anything. I've been brewing for a year since then using this coil every time. Not once has the problem resurfaced. I've used salts in my water, I've used my untreated tap water, I've used a number of adjuncts in my wort and have not had this problem recur no matter what I do. I clean the coil before and after each brew with a star san and a sponge.