How dangerous is it?

[Agentgonzo]

I've found the hop plate does a decent enough job of stopping hops blocking the filter, which on the G30 is the main concern.

I stand corrected. I suppose the holes are the same size as the hop filter and I see the build up on the hop filter every time so the same would be true of the plate. I guess it stops some, but let's some through, and that's good enough.

 

[The-Engineer-That-Brews]

I seem to recall reading that copper is considerably more toxic to yeast than to humans; so if you were getting close to anything dangerous the beer simply wouldn't brew.

Even so, one thing I recommend to people using copper immersion chillers in SS boilers is to prevent any direct electrical contact between the copper and the SS at any point (either above or below the beer).

The problem is that copper and SS have different galvanic potentials, so if you put pieces of them both into an electrolyte like hot, mildly acidic wort you've basically made a battery (like putting a zinc and a copper nail into a lemon, if you ever did that experiment). If the copper and the SS are now connected together e.g. by touching, a current will flow and the copper will start slowly dissolving into the beer... (see Wikipedia: Lasagne Cell)

You can see the general effect in this example of an iron nail with a copper wire wrapped around it. The copper is preventing the iron from oxidising, but is itself slowly dissolving (the blue-green stains in the gel)

 

[MashBag]

I actually stopped using mine and replaced it with a hop plate instead as I got worried the hop spider was preventing the hops from getting sufficient contact with the wort. May have been a complete red herring though.

Some of them do. I tried several finer mesh ones. The MJ is a course 800 mesh. Really does work well. Much better than bags too.

 

[MashBag]

Back to the OP. Copper. This is one of my reasons for opting for a copper coil, rather than a copper counter flow... You can see what is coming into contact with the the wort.

 

[foxy]

I seem to recall reading that copper is considerably more toxic to yeast than to humans; so if you were getting close to anything dangerous the beer simply wouldn't brew.

Even so, one thing I recommend to people using copper immersion chillers in SS boilers is to prevent any direct electrical contact between the copper and the SS at any point (either above or below the beer).

The problem is that copper and SS have different galvanic potentials, so if you put pieces of them both into an electrolyte like hot, mildly acidic wort you've basically made a battery (like putting a zinc and a copper nail into a lemon, if you ever did that experiment). If the copper and the SS are now connected together e.g. by touching, a current will flow and the copper will start slowly dissolving into the beer... (see Wikipedia: Lasagne Cell)

You can see the general effect in this example of an iron nail with a copper wire wrapped around it. The copper is preventing the iron from oxidising, but is itself slowly dissolving (the blue-green stains in the gel)

View attachment 94068

Copper is fine on the hot side on the cold side it is a 'No No' in saying that a copper coil is fine for cooling but no copper in the fermenter. A bit of zinc is fine I have four zinc-plated nuts in my mash tun and the yeast thank me for it.