23 replies to this topic

[pods8]

What material was the bucket? I'm just fishing here a but if it was metallic there could be something going on there.

[BFB]

Soak it in a bucket of star san. That should get it shiny again.

[brewhead]

A brew buddy of mine decided to stick his copper coil in a bucket of 140* PBW. Probably mixed a little more than necessary. It stayed in the bucket for 12 hrs. Of course the PBW temp cooled off during this time. When he checked it 12 hrs later, the entire coil had a nasty black crust all over it except for the areas that was touching the sides of the bucket, which are shiny. When scrubbed off, you can notice some shine underneath. But it would take days to clean this thing.Anybody have a clue of the chemical reaction that caused this?

dunno but i do know that:copper + starsan= shinny

[CaptRon]

Soak it in a bucket of star san. That should get it shiny again.

Maybe Vinegar too? Vinegar is supposed to be great for copper from what I understand, I've never done it though.

[stellarbrew]

According J. Palmer in "How to Brew", oxidizers like bleach and hydrogen peroxide attack copper, quickly causing a layer of black oxides which do not protect the copper as a dull oxide layer does. Rather, since it is formed in alkaline conditions, it will readily dissolve in wort, which is acidic. The yeast would then be exposed to potentially harmful levels of dissolved copper. Best to use vinegar or oxalic acid-based cleansers like Revere Copper and Stainless Steel Cleaner to remove it.

[brewhead]

According J. Palmer in "How to Brew", oxidizers like bleach and hydrogen peroxide attack copper, quickly causing a layer of black oxides which do not protect the copper as a dull oxide layer does. Rather, since it is formed in alkaline conditions, it will readily dissolve in wort, which is acidic. The yeast would then be exposed to potentially harmful levels of dissolved copper. Best to use vinegar or oxalic acid-based cleansers like Revere Copper and Stainless Steel Cleaner to remove it.

on a side note - for this very reason i soak my immersion chiller in sstar san vs putting it in at the end of the boil. i never really understood that practice. oxidized chiller goes into the wort - comes out realitevly shinny. where'd the oxidation go?maybe it's just me...just never could get over that being in my beer. prob wouldn't hurt and i'm sure there are a hundred ppl here who do so...just never sat right with me.

[CaptRon]

on a side note - for this very reason i soak my immersion chiller in sstar san vs putting it in at the end of the boil. i never really understood that practice. oxidized chiller goes into the wort - comes out realitevly shinny. where'd the oxidation go?maybe it's just me...just never could get over that being in my beer. prob wouldn't hurt and i'm sure there are a hundred ppl here who do so...just never sat right with me.

If you brew often enough it shouldn't be a problem.

[brewhead]

i brew maybe once every other month and when i do it's usually in 60 gallon increments.

[zymot]

As I understand it, PBW was originally designed to clean Coors copper heat exchangers.I don't know why it should be turing your copper coil black.zymot

[dagomike]

I'd guess the carbonates are reactive and putting an oxide layer on the copper? Not sure if the water would make a difference. I thought I soaked copper before, but maybe not.

[3rd party JKor]

cupric oxide.

[djinkc]

Saw a pic of that tonight. Strange, but I would just bite the bullet and hit it with the old green scrubby. Had to do that with mine because a starsan soak didn't get it clean, a little extra dose to really lower the pH too - didn't phase it.Anyway it really didn't take that long to get mine cleaned up. Didn't have that black (oxide???) problem though, just crud. And yes, I do give it a nice rinse almost immediately after it's pulled from the wort.

[BrewerGeorge]

Where there any other metals in the bucket with it?

[GaryNConcord]

The PBW acts as an oxidizer, even producing free oxygen so I believe what you got was Cu + O ---> CuO, with the copper having a +2 charge.Take a look at the picture in wikipedia https://en.wikipedia...opper(II)_oxideBased on that, a soaking in a strong vinegar solution could remove it. I would be sure and dump the water and not use it for anything else. It'll have a lot of dissolved copper in it when you're done.

[ThroatwobblerMangrove]

on a side note - for this very reason i soak my immersion chiller in sstar san vs putting it in at the end of the boil. i never really understood that practice. oxidized chiller goes into the wort - comes out realitevly shinny. where'd the oxidation go?maybe it's just me...just never could get over that being in my beer. prob wouldn't hurt and i'm sure there are a hundred ppl here who do so...just never sat right with me.

I actually soak in older star san (star san that is probably still good but has been used quite a bit) and then add it in for the last 15 min of the boil. I figure it's double safe this way and hopefully all of the oxidation gets taken care of in the star san.

[siouxbrewer]

I'd make a paste of white vinegar and table salt, smear it around the coils, then rinse in hot water. The salt will help the vinegar do it's thing and your IC will come out shiny

[Kansan]

Here is the answer to my once blackened copper chiller of last week. I brew 2-3 times a month and my chiller stays pretty darned clean just from that. I do an immersion recirc like Jamil and it is always rinsed immediately afterwords, and I use co2 to blow out the inside coil. I occasionally want to keep it even cleaner by a light soak for about an hour in a 5 gallon plastic bucket with about 1/2oz of PBW. Has worked great this way for a long time. The difference this time was a LOT of PBW say, about 5 ounces- that jar slipped, and a 12 hour soak. Yeah, don't do that...

According J. Palmer in "How to Brew", oxidizers like bleach and hydrogen peroxide attack copper, quickly causing a layer of black oxides which do not protect the copper as a dull oxide layer does. Rather, since it is formed in alkaline conditions, it will readily dissolve in wort, which is acidic. The yeast would then be exposed to potentially harmful levels of dissolved copper. Best to use vinegar or oxalic acid-based cleansers like Revere Copper and Stainless Steel Cleaner to remove it.

So I soaked in Starsan, agitated, and let it sit for a while and not much happened.

Saw a pic of that tonight. Strange, but I would just bite the bullet and hit it with the old green scrubby. Had to do that with mine because a starsan soak didn't get it clean, a little extra dose to really lower the pH too - didn't phase it.Anyway it really didn't take that long to get mine cleaned up. Didn't have that black (oxide???) problem though, just crud. And yes, I do give it a nice rinse almost immediately after it's pulled from the wort.

Talked to DJ a bit and saw his post here. The oxide was so thick from its extended soak, and stupid amount of PBW, that the starsan could not penetrate the layers very well. So it took both elbow grease and chemicals to correct my idiocy. Once it was lightly buffed with a green scrub pad to tear into the layers of oxide it took two 20 minute soaks of 15ml of starsan in 4 1/2 gal of water with some gentle elbow grease in-between and all is well. Shinny and not looking too worse for the wear that I put it through. Thanks for all the suggestions, and to Blktre for starting this thread.