Black copper in spirits?

[res]

So a couple of weeks ago I set my aerating rig up on my modest supply of finished spirits, a couple of litres each of rum, plum brandy and grape brandy. I checked it today and found the copper pipe I'm using has gone black form the fluid level down.
Is this at all normal? Looks a little disturbing. :scared-eek:
The pipe is super thin, not sure of the exact size (about as thick as a pencil) and was washed in citric acid and water prior to use. I bought brand new from Reece refrigeration.
The spirit themselves seem fine and the black wipes off pretty easily.
Anyone seen this before?

[bayshine]

Don't really no mate but am thinking maybe sulfides :think:

[Brendan]

NFI...? :think:

[Zak Griffin]

Thinking it might be the oily shit that comes on new copper?

[TheMechwarrior]

You don't mention cleaning your gear with ethanol, I'm in the oily shit camp with Zak.
Unless it smells of sulfur it's oil/grease. A good caustic bath will help. Followed by your sacrificial solvent run.

[res]

You don't mention cleaning your gear with ethanol, I'm in the oily shit camp with Zak.
Unless it smells of sulfur it's oil/grease. A good caustic bath will help. Followed by your sacrificial solvent run.

That sounds reasonable, it dose seem a little oily and no smell I could detect. Cheers lads :wave:
So maybe another citric acid clean followed by a caustic bath and then a soak in some foreshots maybe? :think:
What would you use for the caustic bath?

[TheMechwarrior]

Sodium hydroxide at 2% m/v is plenty strong enough. Just add the NaOH to cold water and then heat it up. If you add NaOH to hot water you will get an exothermic reaction. ..explosion.
Where gloves and safety glasses and proper clothing when handling NaOH.