Repurposing IC coil for HERMS, Question/pics

As the topic suggests, I'm taking my old 50' copper immersion chiller coil and repurposing it in my HLT as a HERMS coil.

I noticed when I was cutting the copper tubing that theres a pretty dark oxide layer on the inside walls of the coil where I used to run the cooling water through.

I've read Palmer's Metallurgy section in How To Brew, but am still confused.

1) Should I be concerned about this oxide layer dissolving into my wort?

2) Would pumping some diluted oxy/hot water followed by diluted vinegar / hot water through the coil for a while get rid of any nasties AND this oxide layer?

3) Is there a risk of too much copper getting into my finished beer if the vinegar completely removes the oxide layer, leaving a shiny looking inner tube?




Thanks for your help.

I use a copper coil for my heat exchanger, My protocol is to use a small pond pump to recirculate Star-san through the coil as the HLT is coming up to temp. The acid from the Star-san dissolves any copper salts (the blue green crystals) and clears them out of the line before I start running wort through the system. The benefit of this too is when I'm done I have hot sanitizer ready go when I start brewing.

The main thing is you want to use some thing acidic to dissolve any copper salts that could be dissolved into your wort.This will leave your copper very shiny, and a little copper will still be dissolved into your wort but A little copper is good for yeast health, but too much copper can cause illness.