Green wort from HERMS coil

[sa_brewer]

Hey Guys,

My friend runs an aircon shop and they had overstock of soft copper coil so he graciously sponsored me a coil of 50' soft copper for a herms in one of my tanks. The copper was brand new and sealed on both ends. installation went well with no hiccups.

Brewed my first batch today with the new herms coil in place, I ran a percarbonate cleaner through it to make sure everything was clean and then rinsed with water to make sure everything was running fine.

I came in a little low on dough in, so ran the wort through the herms coil to lift the temp to 67c, and obviously to see if it worked when i reached my target temp I left the wort in the coil. it was a 90min mash and not thinking at the end of the mash wanted to get the left over wort out of the coil...and it went straight back into the mash...like I said...wasn't really thinking at that stage.

When it came out it was pretty damn green...now I now that wort is pretty acidic, but what kind of reaction would cause this...I can understand if the coil was eroded, but it was brand new copper? I proceeded to carry on with the boil and pitch as usual but I'm pretty worried that this batch is poisoned by some reaction which took place with that wort that landed up back in the mash...

I really need you guys advice as to whether I should toss or not.

Cheers,
SA Brewer

 

[Sloobie]

Wikipedia says: "When acidic foods are cooked in unlined copper cookware, or in lined cookware where the lining has worn through, toxic amounts of copper can leach into the foods being cooked. This effect is exacerbated if the copper has corroded, creating reactive salts. Actual cooking may not be required for copper to leach into acidic liquids if they are stored in copper for a period of time. Many countries and states prohibit or restrict the sale of unlined copper cookware" (from http://en.wikipedia.org/wiki/Copper_toxicity).

My guess would be that your aircon copper coil is unlined and you ended up with something like Copper Carbonate due to reactions between wort constituents and the copper being sped up by heat (http://en.wikipedia.org/wiki/Copper_carbonate).

You've probably ended up with a very dilute copper salt in your beer. I'd be willing to let it finish out and give it a try, but be aware that copper can be toxic in high quantities.

(Disclaimer: I do not claim to be an expert on such things and the safest choice is obviously just to dump it.)

 

[ScottG58]

I have read you need to clean copper coil by running vinegar through it before first use. I did it recently with a CF chiller and the vinegar comes out green.

I am not a toxicologist. I do think I have also read copper compounds are toxic.

Note that the vinegar should be white vinegar.

 

[sa_brewer]

Thanks for the feedback guys appreciate.

@Sloobie >> do you think it would be possible to build up an oxidised layer similar to the one that forms on aluminium when heated? I'm out in South Africa, what soft copper do you guys use to make your coils, wonder if its any different?

@ScottG58 >> Will run the vinegar solution through, figured the percarbonate clean would have taken anything that would be in there out, but probably not...

The total volume of "green" wort was probably about 1 litre, which is round about 3% of my total volume which was about 40 litres. Is there any chance that the yeast may consume any of teh copper salts? I have heard that any copper interactions pre-boil are OK...but I'm guessing not like this....

Thanks for the help guys, I may just be dumping this batch, and may have to rethink my herms coil....