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Green wort from HERMS coil

Hey Guys,

I checked to see if this was the correct forum to post in so hope it is!

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 :slight_smile: 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 corroded, 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.

SA Brewer

It is possible depending on what the copper had been exposed to, even with new copper, that Verdigris had formed on the inside of the pipe. You would need to soak that copper in an acidic solution and then scrub the inside of the pipe to get rid of it and expose bare copper.

I’ve seen a few HERMS systems made from copper, but the majority of them are stainless steel.

You can get a custom stainless HERMS coil from these people: ... _p_30.html

I would throw away that batch of wort and use the copper for perhaps a wort chiller where you can clean the outside to an acceptable level. Even as a wort chiller you’ll want to clean that copper with vinegar or even star san (let is soak).

If you choose to keep coil, you’ll need to do what distillers do and clean the inside of that tube.

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