Discoloration of stainless pot

[Chipman]

I've had a 5 gallon Polar Ware stainless steel pot for about a year and a half. I've used it to heat strike water, as my kettle, and for decocting. It's been heated with electric stove coils, and a propane burner. After my last decoction I noticed a section on the bottom inside the pot that was purplish, yellowish, and greenish in sort of concentric circles.

I also use a keg as my kettle. It's developed some pock mark looking dotties on the bottom of the inside, some stick up, some are smooth but just little dark dots.

Anyone else had this happen, or know why, or if it's going to be a problem? Haven't noticed any off flavors from water or wort that's been boiled in either but want to nip it in the bud if it eventually will.

Thanks!

 

[GilaMinumBeer]

The former sounds like scorching from a very hot flame.

The latter sounds like a galvanic pitting reaction. Do you ever leave water in the pot after cleaning? Have you ever tried re-passivating your stainless?

 

[Schnitzengiggle]

The iridescent colors in your HLT/decoction pot are more than likely normal, similar to the coloration that occurs on chrome headers, or hot exhuast manifolds. If it is bothersome try some Barkeeper's friend, the stuff is magical on stainless steel.

As for your Keggle, that is strange, try some BKF on that too.

I know these probably aren't the answers that you are looking for but they are my .02.

Good luck!

 

[SPLASTiK]

After a brewday I stuck an empty keggle on the propane burner and not realizing I forgot to fill it up with cleaning water, lit it and stepped away for a few minutes to return to a strange burning smell. I got a huge rainbow of colors inside the bottom.

A few doses of barkeeper's friend and a scrubbie made for stainless got it all cleaned off.

 

[Schnitzengiggle]

After a brewday I stuck an empty keggle on the propane burner and not realizing I forgot to fill it up with cleaning water, lit it and stepped away for a few minutes to return to a strange burning smell. I got a huge rainbow of colors inside the bottom.

A few doses of barkeeper's friend and a scrubbie made for stainless got it all cleaned off.

Like I said, the stuff is MAGICAL!

 

[GilaMinumBeer]

AND being that it is Oxalic Acid it is effective at catalyzing the passivation process.

 

[Schnitzengiggle]

AND being that it is Oxalic Acid it is effective at catalyzing the passivation process.

I'll assume that is why after a good scrub w/BKF and even after a really good rinse there is a powdery film that needs to be polished off.

 

[Chipman]

Aye I do leave water in it after cleaning, which does indeed contain chlorine. Never again! Guess I ought pick me up some BKF and scrub away to get some of that off. Interesting stuff stainless steel.

From what I understand passivating just requires that the tainted layer be scrubbed off and as the new layer interacts with oxygen it will re-passivate.

I'm also looking to remove any lead I can from the top layer of brass if anyway has experience with that.

Cheers gents!

 

[DeafSmith]

I'm also looking to remove any lead I can from the top layer of brass if anyway has experience with that.

Cheers gents!

http://www.howtobrew.com/appendices/appendixB.html

Scroll down to "Cleaning Brass"