Passivation Problems - Ideas Anyone?

[Tippsy-Turvy]

I'm still getting dark residue sh*t on my keg walls that's getting into my beers. My first time serving from the keg was at a party last weekend and the beer came out blackened and tasted metallic.

After sifting through many threads, I still can't solve the problem. Here are the steps I've taken so far:

1) On receiving the keg many months ago, it was disassembled, soaked in PBW overnight, scrubbed thoroughly with a kitchen Brite pad, rinsed and left sitting around with the lid loosely on for months. Not surprisingly the first scrubbing produced lots of black residue.

2) Pre-kegging the beer, the keg was rinsed with water, partially filled with diluted starsan, shaken multiple times and left overnight.

3) Post the party humiliation, the keg was soaked with PBW overnight, scrubbed down with a Brite pad and rinsed. The rinse water was still black (see photo below)!


4) After going thro many threads again, I then scrubbed the inside walls again with the Brite pad, rinsed, sprayed on 50% solution of concentrated phosphoric acid multiple times over a period of about 2 hours and then rinsed with reasonably hot water. After it dried, wiping the walls with a tissue still produced the black residue (see second photo)!!!! Aaaargh.


Shouldn't the keg be passivated from just sitting around for months?? Why wouldn't it be passivated after so many scrubs and spraying on the acid??

 

[jcav]

From the photo it looks like the pad your using is taking off a layer of metal. It may be too abrasive. I only use a white scrub pad on my stainless kegs and kettles because the green ones can be too abrasive. If that is whats going on the black is small particles of metal like very small shavings. At least from the photo that's what it appears to be. Try rinsing the heck out of it and let it dry. Then wipe it again and see if you get more black reside.....

John

 

[Tippsy-Turvy]

I only use a white scrub pad on my stainless kegs and kettles because the green ones can be too abrasive

That's an interesting point. Is your white pad just sponge? If so, I can try rinsing again and wiping down with the sponge side of the Brite pad.

 

[jcav]

It actually has a handle on top and on the bottom part of it is a white sponge and the other half is a white scrubby, but it is not very abrasive at all. Just enough to get all the grime and stuff off without scratching. You can get them at Walmart or supermarkets.

John

 

[jcav]

Try rinsing it out and wiping it down with the sponge and see what happens. Your problem might be solved.

John

 

[akthor]

Yeah I would say your pad is too abrasive. Your not scrubbing a dirty frying pan! You should never have to use anything beyond soaking and a sponge to clean a keg.

I'm not sure but you've probably introduced micro scratches into the surfaces. You might have to do something to restore the finish.

 

[jcav]

This is true for me also. I only use the WHITE scrubby on my boil kettle and my conical fermenter. I have a keg washer for my kegs and I rinse it out, and then run PBW, rinse, and then run Sani-Clean through it.

John

 

[Tippsy-Turvy]

I'm not sure but you've probably introduced micro scratches into the surfaces. You might have to do something to restore the finish.

Just great. Well, i'll have to look into restoring the finish later.

To be clear, your concern about the micro scratches is from the sanitation perspective, right?