Brown residue inside still and off smell in water run

[LocalRepeater]

Hello, not sure if this is the correct place for this post so sorry in advance.

I've built a reflux still out of copper and following advice on the forum did a vinegar run with a 50/50 mix of vinegar and water. After doing this I cleaned out the still and there seem to be a lot of brown residue inside the reflux column.

I cleaned as much of the residue out as possible with a stainless steel scrub for at least 20 minutes in hot soapy water, but even after this when I run my finger around the inside of the reflux column my finger would discolour slightly and the inside of the column was still not totally shiny.

I then tried a water run hoping it would clean out some of the residue. The water came out completely clear but had a sweet vinegary smell to it.

Any ideas what caused the brown residue to appear and my best bet for getting rid of it? or what is cause of the smell in the distilled water?

[fizzix]

Congrats on a build, 'Repeater!
It's likely flux.
You did only part of the cleaning run with the vinegar & water, though. Follow through with a sacrificial alcohol run to complete the job.
Vinegar/water gets some cleaning done, and the alcohol run gets what the douche run missed.

Make your sacrificial run cheap & easy like Birdwatcher's and for God's sake, don't drink it!
Thus sacrificial.

[Samyguy]

Maybe try a citric acid bath,

[NZChris]

I'm getting concerned about how many new still owners/builders are showing up here not knowing to follow up a vinegar run with a sacrificial alcohol run, plus their not knowing that the product of the sacrificial can be toxic.

Where did you get your cleaning advice from, LocalRepeater?

[LocalRepeater]

I am aware that I need to do a sacrificial run, but the brown residue was unexpected so I wanted to figure out what was going on before continuing.

Thanks for the advice, I will just try do a sacrificial run and see if everything clears up.

[zed255]

Also remember fresh copper takes a while to gain a patina and you do want a nice patina. If you scrub down to bright metal repeatedly you will seem to always have residues. Relax, finish your initial clean and run it, rinse and air dry is all you need long term barring a puke or running something really oily.