counterflow chiller and vinegar

I have an old counterflow chiller that I am cleaning up. The outer tubing is transparent vinyl and there is some visible bluish green corrosion and mineral deposit in the water side of the chiller. Never was too concerned about cleaning that part...

So for the 'beer side' of the chiller I did a soak in PBW followed by a soak in vinegar (room temperature, maybe 20 mins). The vinegar that came out of the chiller had a blue tint to it. No chunks or anything like that.

I haven't soaked copper in vinegar for a while so I forget. Is this just a small amount of copper leaching into the vinegar, or do I have have some serious corrosion on the inside as well? Should I go ahead and use it?

The vinegar is acidic and corrodes the copper, which is probably what you saw. I left my CFC coil full of star-san for about a week one time and when I drained it, the first several ounces of liquid that came out were a rich turquoise color. The CFC still works, although I'm guessing the wall thickness has gone from 0.060" to 0.050" or something like that.

Telkl us what your results were

Copper does not "thin out" evenly in response to acidic or galvanic action.

Yah metal comes off from every where there is such action but there are places in any pipe where the action if more intense. Lots of places.

Here is how I know:
I bought this ancient house and it came with scads of old copper piping. The water must have changed at some time during the previous owner's history here. In the alternate he had it all replaced - which is a pretty good possibility since his BIL was a plumber and had done extensive work in the building.

Anyway I digress:
The copper pipes started leaking ab bout ten years after I bought the place.
Leaking not at the joints but from itty bitty pin holes. I'd be in the cellar and there'd be little vaporizer sized spray holes in the piped all over the place.

It was quite disconcerting. and happen most in pipes that got regular use and not so with those that didn't. It's a big house we actually have two bathrooms that see almost no use. so the distinction was pretty clear: Lots of use = holes. Not much use = no holes. Not rocket science.

Well, I had the water tested: Lots of minerals lots of iron lots of acid. No wonder it tasted so good.

So I put in a dual stage softener with neutralizing and deionizing stages and the problems is solved.

But ever the curious sort I had to have me a look see at those leaky pipes i had replaced.

I cut 'em open lengthwise on my table saw.

Inside they had little conical shaped pit holes where you could see light.

From that I deduced that there are places in the copper where it's just more susceptible to acid or electrolysis than other areas of the same pipe. Those places show up as conical pits.

Your chiller is a soft copper. I am unsure whether that means is alloyed to be soft or it the softness is just a factor of the heat treatment. Yes, you can make copper hard or soft by doing things to it. Hammering makes it hard and brittle, heating to cherry red and quenching it in water makes it soft, quenching in air hardens it. None of that should much affect how it responds to acid and electtrolysis.

So I'd guess that you have little pits in your chiller from a long soak in an acid rich solution. The proof is the colored ejaculate. Whether that means your chiller is Kaput is anybody's guess.

But, I'd be most resistant to the idea of soaking a copper counter flow chiller in any acidic solution.