Black Pot-Homebrew Question

[VERO1]

Asking a question for my son. He has an aluminum turkey frying pot that he uses to cook home brew in. After the last batch he washed it with some type of homebrew equipment sanitizer. When the pot dried it was black inside. Whatever he used etched the metal. Any ideas how to restore the pot, or any ideas if the black surface will affect the next batch. I always used the old blue granite wear pots but I'm dumb and old fashioned!

[KaNaPaPi]

Hydrochloric acid should do the trick (CLR or Lime Away). If that doesnt do it, any automotive aluminum polish would work. After using either, wash with hot soapy water.


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[Raoul]

Before you get too energetic about scrubbing the pot you might want to look at this homebrew thread

 

http://www.homebrewtalk.com/f11/aluminum-pot-turned-black-259089/

[VERO1]

Ah! Thanks Raoul the boy child will be thrilled!

[Raoul]

Ah! Thanks Raoul the boy child will be thrilled!

Hope it helps.

[FUJIMO]

I wasnt going to chime in because I dont brew but I have several stainless and aluminum pots for deep frying and pressure cooking and canning and they all have that layer. First time it happened I freaked but after reading the manual the mfg. said it would happen. Never researched further but its nice to know now :)

[peejman]

Right.  It's effectively aluminum rust.... aluminum oxide.  It's the reason why the cloth comes off black whenever you use metal polish on something aluminum. 

 

TMI alert:  Aluminum is one of those nifty metals that does what's called "self passivation".  When bare alminum is exposed to air, the oxide layer that forms is much harder than the aluminum itself and solid so it completely covers the aluminum and prevents further corrosion.  The whole process typically happens within a few seconds of exposing bare aluminum to air.  However, the oxide layer is exceedingly thin so it's easily scratched off and the process starts again. 

 

As stated above, the cleaner has etched the aluminum pot and removed that oxide layer, only to have it return in a much greater thickness because of the residual cleaner on the surface.  If he really wants the black gone, a scotch-brite pad will take it off.