Using peracetic acid with copper

[Naich]

I steralised my FV immersion chiller, which is made from copper using peracetic acid. After I'd put it in the wort, I noticed that the run off from where I had sprayed it had a green tint to it. Obviously this stuff is very corrosive to copper, but does anyone know if the product is likely to be poisonous?

[Aleman]

DO not use peracetic with copper . . . copper catalyses the breakdown to acetic acid and Peroxide plus the peroxide to Water and Oxygen. . . . And it eats the crap out of the copper . . . It's great for cleaning the grunge out of copper tube every now and again though.

The sludge is possibly copper acetate, and most (all??) copper salts are poisonous to a degree . . . Of course the good thing about yeast is that they absorb copper so even though the levels of copper in a wort from a coper 'copper' are quite high the levels in the finished beer is actually quite low. . . . Midlands craft brewers did an analysis of this about 18 months ago, where they had 3 samples analysed from breweries with increasing amounts of copper in the plant. . . the beers came out roughly equal in copper content . . . the worts had some strange results.

[Naich]

Oh bugger. I'm not quite sure how to steralise it now. I read somewhere that you aren't supposed to use bleach on copper. Cook it in the oven, maybe?

Copper acetate is nasty stuff all right. Will the yeast metabolise it or have I just produced a batch of poisoned beer?

[Aleman]

You sanitise the Immersion Chiller, by putting it in boiling wort 15 minutes before the end of the boil . . . beyond cleaning it off at the end of a brewing session (and possibly before use) there is little need to use any disinfecting agent on the copper . . . which acts as a natural biocide anyway.

Based on the results I've seen for copper 'absorption' by yeast I wouldn't worry about any 'contamination'.

The only possible issue you may have is a haze cause by the metal ions (copper) joining with phenols creating a 'metal' haze.

[Naich]

Based on the results I've seen for copper 'absorption' by yeast I wouldn't worry about any 'contamination'.

The only possible issue you may have is a haze cause by the metal ions (copper) joining with phenols creating a 'metal' haze.

Thanks for the info Aleman. I had a google around but couldn't get a definitive answer on it. The actual amount of copper acetate I've put into the wort will be quite small. This isn't a chiller for the boiler, by the way - it's for the fermenter.