Plastic Liquid Disconnect... Green residue? Patina? Finish worn off?

[Ashevillain]

I went to go clean some disconnects before doing a closed transfer and noticed that the insides of the barbs were now looking like copper not stainless. I even noticed some green spherical buildup, (hoping patina due to copper), upon looking inside the barb. Whats the deal? It seems like it would be ideal to either use stainless/aluminum barbs or at least use copper without a finish that eventually dissolves in your lines... I guess copper is good to go for finished beer though the idea of exposing finished beer to copper just feels off. Not a fan of penny flavor. Has anyone else noticed this with their plastic liquid barbs?

 

[The_Bishop]

What barbs are you referring to?

 

[Ashevillain]

My plastic disconnects include barbs to connect the lines to, they are built into the disconnect. I happened to have a few new disconnects lying around and can confirm the new ones have some sort of matching "stainless looking" finish on the inside. Im cleaning them all now, guess since there are no other threads about this it doesn't cause any issues, just found it strange and a bit misleading on the manufacturers behalf.

 

[Ashevillain]

This article on metallurgy seems to confirm that what lies underneath whatever silver finish thats already dissolved into my beer on these disconnects is copper. Further, exposing copper to wort for extended periods of time will promote corrosion and lead to the development of Verdigris, a toxic compound easily soluble in beer. Some of these disconnects are not older than 2-3 months. Pretty lame.

 

[indolent]

This article on metallurgy seems to confirm that what lies underneath whatever silver finish thats already dissolved into my beer on these disconnects is copper. Further, exposing copper to wort for extended periods of time will promote corrosion and lead to the development of Verdigris, a toxic compound easily soluble in beer. Some of these disconnects are not older than 2-3 months. Pretty lame.

That's concerning. I should probably check mine. I usually just clean in place so I haven't disconnected the tubing in a long time.

Might have to look into investing in some stainless ones.

 

[Dcpcooks]

I've noticed a degradation of the metal if I leave it to long in start San. I was under the impression that was brass not copper but I could be wrong.

 

[bucketnative]

I've noticed a degradation of the metal if I leave it to long in start San. I was under the impression that was brass not copper but I could be wrong.

Brass is a copper alloy... Copper and zinc (plus trace elements), to be exact. Green corrosion from brass is due to the copper.

If it's chrome or nickel plated metal, that can help stave off corrosion. Once the plated finish gives way to the underlying brass, corrosion will proceed. No plating is 100% perfect and probably has some very small defects. If you leave the plated pieces soaking in an acid solution (Starsan), those small imperfections will present excellent sites for pit corrosion of the underlying brass.

 

[Dcpcooks]

Brass is a copper alloy... Copper and zinc (plus trace elements), to be exact. Green corrosion from brass is due to the copper.

If it's chrome or nickel plated metal, that can help stave off corrosion. Once the plated finish gives way to the underlying brass, corrosion will proceed. No plating is 100% perfect and probably has some very small defects. If you leave the plated pieces soaking in an acid solution (Starsan), those small imperfections will present excellent sites for pit corrosion of the underlying brass.

Thanks, learn something new every day!

 

[kiwipen]

Where did you get the disconnects?

 

[Moarhops]

I was just about to post a question asking about this! My disconnects are of a similar age and starting to show patches of black and green. Can they be cleaned up or do they need to be chucked out? Doesn't seem very long for them to have lasted...

 

[kiwipen]

Once the chrome, nickel or whatever coating has worn of it wont come back.

Were did you buy those disconnects?

 

[Moarhops]

Once the chrome, nickel or whatever coating has worn of it wont come back.

Were did you buy those disconnects?

Not sure where the OP bought theirs from but I picked up mine from Keg Kingdom (UK website). Very disappointing...

 

[kiwipen]

Not sure where the OP bought theirs from but I picked up mine from Keg Kingdom (UK website). Very disappointing...

Do you know if they are the CMB branded one or generic chinese?

 

[Moarhops]

There's no sign of any CMB branding, just the letter "S" inside a cog on the side. Guessing this must be a generic Chinese version. Lesson learned!