Aluminum Pot Turned Black?

After about my 10th 5 gallon batch I noticed the inside of my aluminum pot has turned black around the boil line (typically 3.5 gallon mark) but there are also black streaks down to the bottom of the pot on the inside as well as a thick ring around the top inside the pot.

Is this normal? After cleanup one day I left OxyClean and water solution in my pot so I could help scrub it out, that is when it was really noticed.

I scrub with some elbow grease and the black doesn't come off, so I am not sure if this will ruin my next batch of beer?

Any help is appreciated.

Do NOT scrub the inside of an aluminum brew pot!!!

Boiling water in an aluminum brew pot will build up an oxidation layer on the aluminum, which prevents the aluminum from leaching into your beer. That's likely the black coloration you're seeing, and you WANT that!

The inside of an aluminum brew pot should be gently washed only - make sure any big chunks of stuff is out of there, make sure it looks clean - but never scrub!

Thanks! What I meant by "scrub" was using a soft sponge with some elbow grease. Is that bad too? Maybe it creates little scratches in the aluminum?

If not, how the hell am I supposed to clean the thing?

Thanks! What I meant by "scrub" was using a soft sponge with some elbow grease. Is that bad too? Maybe it creates little scratches in the aluminum?

If not, how the hell am I supposed to clean the thing?

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Hmm....I don't think you understood the last post. You NEED to have that stuff in your pot. This is the oxidation layer that prevents aluminum from leaching into your wort during boiling. If you choose to have an aluminum pot, then you are choosing to have a pot with an oxidation layer built up on the inside. THIS SHOULD NOT BE CLEANED, or your beer will taste metallic. Just clean the pot with dish soap and a dish brush like you would a plate, but DON'T try to clean through the gray/black oxidation layer!! YES to the soft sponge. NO to the elbow grease!

FYI - Aluminum starts building it's oxide layer amazingly quickly. If you scrub a bit, then maybe soak in oxiclean to promote the oxide layer. It doesn't have to be thick to be effective.

No, I completely understand. What I meant was to clean the built up crusted wort/hops that happens around the boil line.

I haven't been trying to scrub through the black layer, just curious what it was.

It really is only on the top 1/3 of the pot. Should I soak it in more oxlyclean to try to get the full pot oxidized?