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Blue Pwb Solution From My Plate Chiller

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mateostojic

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Hello brewers,

I am having a bit of an issue with my plate chiller. When i soak it in PBW, the solution turns blue/turquoise. I know from previous experience that when aluminium is in contact with PBW solution, it causes it to go blue, and i have read that copper does the same. However, this shouldn't happen with stainless, so i am a bit concerned.

Does it mean that something is stuck in my chiller? No solids come out of the chiller in the solution, its clear with a distinct blue/turquoise tinge.

Has anyone else had this issue? I have searched around a fair bit, but could not find anything.

I dilute the PBW at the correct ratio. I have double checked this.

Cheers,
Mate
 

Adam Howard

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Stainless plate chillers are soldered with copper. I've seen a blue tinge come out if I soak mine in PBW for ages.
 

MHB

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The plates are brazed together by plating the parts that meet (around the edges) with copper, pressing the whole mass of plates together then heating the lot until the copper melts and fuses the heat exchanger into a solid block.
You have some exposed excess copper inside that is being attacked by either the wort but more likely your cleaning chemicals and its forming a copper salt which is giving the blue colour.
The excess should be able to be etched away with an acid; I would probably choose dilute nitric acid, until you get rid of the copper this will keep happening.
If you wash the heat exchanger just before you use it to flush out any copper salts (again I would use a dilute acid and then lots of clean water) you should be fine. Copper salts arent good for you (except in trace amounts) they taste like shit and can harm the yeast so best to avoid them if possible.
I dont know where you got the unit; you could consider returning it if that option is open, but if you pre-clean thoroughly it will be safe enough to use and the problem should eventually go away.
Mark
 

mateostojic

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The plates are brazed together by plating the parts that meet (around the edges) with copper, pressing the whole mass of plates together then heating the lot until the copper melts and fuses the heat exchanger into a solid block.
You have some exposed excess copper inside that is being attacked by either the wort but more likely your cleaning chemicals and its forming a copper salt which is giving the blue colour.
The excess should be able to be etched away with an acid; I would probably choose dilute nitric acid, until you get rid of the copper this will keep happening.
If you wash the heat exchanger just before you use it to flush out any copper salts (again I would use a dilute acid and then lots of clean water) you should be fine. Copper salts arent good for you (except in trace amounts) they taste like shit and can harm the yeast so best to avoid them if possible.
I dont know where you got the unit; you could consider returning it if that option is open, but if you pre-clean thoroughly it will be safe enough to use and the problem should eventually go away.
Mark
Thanks Mark. I have some citric acid handy which i will dilute and soak. Hopefully it works.

Cheers,
Mate
 

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