Star San and copper wort chiller

[rodthebod]

I store my wort chiller in a plastic tub with a bottle of star San and a few other items. Somehow the star San bottle was left open and spilled in the bottom of the tub and part of my chiller was left submerged in the pure star San liquid for several months and is now green. If I clean this up and get rid of the discoloration is the chiller still safe to use?
Thanks for your help

 

[Broken Crow]

I use Star San to clean my CFC periodically by letting it sit about a half-hour inside then flushing thoroughly. When that same copper tubing was in it's previous IC form, I used Star San to clean it's exterior periodically, but once did leave it immersed too long and got a small bit of vertigris... I just scrubbed it off, first with steel-wool and then a pot-scrubber and gave it a wash and a soak....worked fine with no reactive off-tastes.

 

[bruce_the_loon]

From a chemical perspective, yes it is safe. If you can get the green patina off the surface, then the copper will be fine chemically. This site seems to have a few good ideas of how to do it. How Do You Remove Green Corrosion from Copper Pipes? - GoodBee Plumbing

From a mechanical integrity perspective, there may be issues. undiluted StarSan is a reasonably strong acid and the corrosion may have thinned out the walls of the copper pipes or even corroded through the metal completely. Some copper piping has very thin walls. You'll have to examine the entire affected area carefully, maybe use digital calipers if you have them to see if the pipe is noticeably thinner than unaffected areas.

If you are happy there are no holes, I'd conduct a pressure test. Find a way to shut off the outflow side, then fill it with water from your faucets to blow any air out the chiller, then close the outflow side and open your faucet all the way. Do it in a bucket in case there are leaks.

 

[IslandLizard]

[...] is the chiller still safe to use?

Absolutely, as long as you remove all the copper green first (Starsan does that rather quickly), and it didn't eat a hole in the copper.

You may need a stiff brush, or perhaps even some fine sandpaper to remove all that copper green. Don't breathe the dust!

 

[youngdh]

I use Star San to clean my CFC periodically by letting it sit about a half-hour inside then flushing thoroughly. When that same copper tubing was in it's previous IC form, I used Star San to clean it's exterior periodically, but once did leave it immersed too long and got a small bit of vertigris... I just scrubbed it off, first with steel-wool and then a pot-scrubber and gave it a wash and a soak....worked fine with no reactive off-tastes.

Star San is not a cleaner, it’s a sanitizer. Anything that will be place in the boil doesn’t need sanitizing ahead of time. Anything touching the wort once it drops below 180°F does.

 

[Broken Crow]

Star San is not a cleaner, it’s a sanitizer. Anything that will be place in the boil doesn’t need sanitizing ahead of time. Anything touching the wort once it drops below 180°F does.

It gets PBW and hot water after every brew, but as copper is reactive, it does tarnish internally, thus the periodic cleaning with Star San to remove that tarnish.

 

[rodthebod]

I use Star San to clean my CFC periodically by letting it sit about a half-hour inside then flushing thoroughly. When that same copper tubing was in it's previous IC form, I used Star San to clean it's exterior periodically, but once did leave it immersed too long and got a small bit of vertigris... I just scrubbed it off, first with steel-wool and then a pot-scrubber and gave it a wash and a soak....worked fine with no reactive off-tastes.

I scrubbed it all off. I should be good to go now. Thanks for the help.

 

[rodthebod]

From a chemical perspective, yes it is safe. If you can get the green patina off the surface, then the copper will be fine chemically. This site seems to have a few good ideas of how to do it. How Do You Remove Green Corrosion from Copper Pipes? - GoodBee Plumbing

From a mechanical integrity perspective, there may be issues. undiluted StarSan is a reasonably strong acid and the corrosion may have thinned out the walls of the copper pipes or even corroded through the metal completely. Some copper piping has very thin walls. You'll have to examine the entire affected area carefully, maybe use digital calipers if you have them to see if the pipe is noticeably thinner than unaffected areas.

If you are happy there are no holes, I'd conduct a pressure test. Find a way to shut off the outflow side, then fill it with water from your faucets to blow any air out the chiller, then close the outflow side and open your faucet all the way. Do it in a bucket in case there are leaks.

I was able to clean it off with vinegar and steel wool. I did a close inspection and it looks ok, definitely some section loss but no holes as far as I can tell. but I’m going to do a pressure test like you recommended. Thanks a lot for your help.

 

[rodthebod]

Absolutely, as long as you remove all the copper green first (Starsan does that rather quickly), and it didn't eat a hole in the copper.

You may need a stiff brush, or perhaps even some fine sandpaper to remove all that copper green. Don't breathe the dust!

I was able to remove the verdigris with vinegar per John Palmers recommendation. It took some scrubbing with steel wool but I got it all off. Thanks a lot for your help.