Author Topic: Passivating New Stainless Steel  (Read 6895 times)

Offline diver-bob

  • 1st Kit
  • *
  • Posts: 2
Passivating New Stainless Steel
« on: August 21, 2018, 02:54:21 am »
Just wondering about whether or not to passivate a new kettle.  I assume this is normally done in commercial breweries.  I understand this can be done on the homebrew scale with Star San.  Any other thoughts or suggestions?

Offline ynotbrusum

  • Official Poobah of No Life. (I Got Ban Hammered by Drew)
  • *********
  • Posts: 4327
Re: Passivating New Stainless Steel
« Reply #1 on: August 21, 2018, 05:56:25 am »
I used TSP per the instructions that came with my Stainless BrewBucket.  The TSP is different these days, because it isn’t allowed in several jurisdictions - I think the new stuff doesn’t contain the phosphates, but I used it anyway.
Hodge Garage Brewing: "Brew with a glad heart!"

Offline goose

  • Senior Brewmaster
  • ******
  • Posts: 1077
Re: Passivating New Stainless Steel
« Reply #2 on: August 21, 2018, 07:31:15 am »
Just wondering about whether or not to passivate a new kettle.  I assume this is normally done in commercial breweries.  I understand this can be done on the homebrew scale with Star San.  Any other thoughts or suggestions?

Yes, it is always a good idea to passivate them when new or at least once per year (more frequently if you brew often).  Give them a good cleaning with TSP or PBW then passivate them with Star San at the dilution rate of 1 oz. per gallon of water.  I normally let the mixture sit in the kettle for about a half hour or so, wetting the sides frequently with a sponge if you don't want to completely fill the kettle (which can get a bit expensive).  This was recommended by SS Brewtech when I purchased my conical and it works very well.
Goose Steingass
Wooster, OH
Society of Akron Area Zymurgists (SAAZ)
Wayne County Brew Club
Mansfield Brew Club
BJCP Certified
AHA Governing Committee Member

The Beerery

  • Guest
Re: Passivating New Stainless Steel
« Reply #3 on: August 21, 2018, 07:42:50 am »

Offline Bilsch

  • Assistant Brewer
  • ***
  • Posts: 226
Re: Passivating New Stainless Steel
« Reply #4 on: August 21, 2018, 10:11:57 pm »
Very true. Phosphoric acid doesn't passivate stainless. You need nitric or citric acid to do the job correctly. Nitric acid as not fun to work with or dispose of but citric is, and it's cheap too. Just use a 4% solution at 160 to 180f for a couple hours. Save your Starsan for sanitation.

Offline mabrungard

  • I spend way too much time on the AHA forum
  • ********
  • Posts: 2819
  • Water matters!
    • Bru'n Water
Re: Passivating New Stainless Steel
« Reply #5 on: August 22, 2018, 06:29:43 am »
Passivation is only needed on freshly machined or formed stainless steel. Passivation is NOT needed or required under normal brewery use. I'm confused as to why anyone would go through that effort more than once?

With regard to homebrewing scale, citric acid passivation is the most accessible method. Nitric acid is a very hazardous material.
Martin B
Carmel, IN

BJCP National
Foam Blowers of Indiana (FBI)

Brewing Water Information at:
https://www.brunwater.com/

Like Bru'n Water on Facebook
https://www.facebook.com/Brun-Water-464551136933908/?ref=bookmarks

Offline goose

  • Senior Brewmaster
  • ******
  • Posts: 1077
Re: Passivating New Stainless Steel
« Reply #6 on: August 22, 2018, 06:47:08 am »
Starsan does NOT passivate SS. Here is the link from our resource section...

http://www.lowoxygenbrewing.com/wp-content/uploads/2018/08/ASTM-A967-Standard-specification-for-chemical-treatments-for-stainless-steel-parts.-1.pdf

I agree that nitric acid is the best way to passivate stainless, although it is very dangerous to use.  However, I have used the StarSan dilution I previously mentioned to remove beer stone from my boil kettle and it shines up the stainless just fine.  That is also what SS Brewtech recommends for their conicals.
Another product that does well on stainless is Bar Keepers Friend.  It is oxalic acid and really shines up the outside of my boil kettle.

Martin's idea of citric acid is also a good one.
Goose Steingass
Wooster, OH
Society of Akron Area Zymurgists (SAAZ)
Wayne County Brew Club
Mansfield Brew Club
BJCP Certified
AHA Governing Committee Member

Offline ynotbrusum

  • Official Poobah of No Life. (I Got Ban Hammered by Drew)
  • *********
  • Posts: 4327
Re: Passivating New Stainless Steel
« Reply #7 on: August 22, 2018, 07:46:05 pm »
The SSBrewbucket site indicates that the StarSan treatment can be used to paasivate at the rate of one ounce per gallon of water.  The TSP is merely a cleaner - my recollection was close, but skewed.  Glad to hear that passivation is generally unnecessary.
Hodge Garage Brewing: "Brew with a glad heart!"

Offline hopfenundmalz

  • Global Moderator
  • I must live here
  • *****
  • Posts: 10314
  • Milford, MI
Re: Passivating New Stainless Steel
« Reply #8 on: August 23, 2018, 06:08:25 am »
Oxygen does the passivation. Nitric acid cleans the surface and supplies Oxygen. Citric acid? Anyone know.

A clean surface of SS will passivate quickly when exposed to air.
Jeff Rankert
AHA Lifetime Member
BJCP National
Ann Arbor Brewers Guild
Home-brewing, not just a hobby, it is a lifestyle!

Offline ynotbrusum

  • Official Poobah of No Life. (I Got Ban Hammered by Drew)
  • *********
  • Posts: 4327
Re: Passivating New Stainless Steel
« Reply #9 on: August 23, 2018, 11:55:24 am »
Oxygen does the passivation. Nitric acid cleans the surface and supplies Oxygen. Citric acid? Anyone know.

A clean surface of SS will passivate quickly when exposed to air.

That is how I remembered it many years ago when I bought my first stainless kettle - I am now at a point where my recollection gets foggy on where I heard things, so I went back to the SS BrewBucket info on their website and I suppose that they are being overly cautious with the suggested process.  O2 exposure is enough for me (I am not fabricating these items, after all....). 

Thanks, Jeff! 
Hodge Garage Brewing: "Brew with a glad heart!"

Offline Richard

  • Brewmaster
  • *****
  • Posts: 650
Re: Passivating New Stainless Steel
« Reply #10 on: August 23, 2018, 03:54:38 pm »
Passivation produces an oxide layer that prevents rust - that is what makes it "stainless" steel (the German name is rostfrei or rust-free). Newly manufactured items need passivation because the machining and welding can damage the oxide layer. The manufacturer should do this. In normal use, if you don't see any rust then you don't need to passivate.
Original Gravity - that would be Newton's

Offline LeeH

  • Cellarman
  • **
  • Posts: 45
Re: Passivating New Stainless Steel
« Reply #11 on: August 24, 2018, 06:06:50 am »
Oxygen does the passivation. Nitric acid cleans the surface and supplies Oxygen. Citric acid? Anyone know.

A clean surface of SS will passivate quickly when exposed to air.

How long does it take when just using air?


Sent from my iPad using Tapatalk Pro

Offline diver-bob

  • 1st Kit
  • *
  • Posts: 2
Re: Passivating New Stainless Steel
« Reply #12 on: August 24, 2018, 06:46:14 am »
Just wondering about whether or not to passivate a new kettle.  I assume this is normally done in commercial breweries.  I understand this can be done on the homebrew scale with Star San.  Any other thoughts or suggestions?

Yes, it is always a good idea to passivate them when new or at least once per year (more frequently if you brew often).  Give them a good cleaning with TSP or PBW then passivate them with Star San at the dilution rate of 1 oz. per gallon of water.  I normally let the mixture sit in the kettle for about a half hour or so, wetting the sides frequently with a sponge if you don't want to completely fill the kettle (which can get a bit expensive).  This was recommended by SS Brewtech when I purchased my conical and it works very well.
Thanks for the reply Goose!  The main reason I asked this question is because my new kettle arrived with a jungle of scratch marks.  This happened because the grain basket (BIAB system) was shipped inside the kettle and the feet on the basket were grating away at the bottom and sides of the kettle during shipping.

Cheers!

Offline macbrews

  • Assistant Brewer
  • ***
  • Posts: 172
Re: Passivating New Stainless Steel
« Reply #13 on: August 24, 2018, 09:36:21 am »
Sounds like they should “passify” you and send you new undamaged goods.....


Sent from my iPhone using Tapatalk

Offline hopfenundmalz

  • Global Moderator
  • I must live here
  • *****
  • Posts: 10314
  • Milford, MI
Re: Passivating New Stainless Steel
« Reply #14 on: August 24, 2018, 10:30:59 am »
Oxygen does the passivation. Nitric acid cleans the surface and supplies Oxygen. Citric acid? Anyone know.

A clean surface of SS will passivate quickly when exposed to air.

How long does it take when just using air?


Sent from my iPad using Tapatalk Pro

It is a rapid reaction. Minutes or less.
Jeff Rankert
AHA Lifetime Member
BJCP National
Ann Arbor Brewers Guild
Home-brewing, not just a hobby, it is a lifestyle!