Passivation - fill the entire kettle?

HomeBrewTalk.com - Beer, Wine, Mead, & Cider Brewing Discussion Community.

Help Support Homebrew Talk:

pretzelb

Well-Known Member
Joined
Jul 8, 2009
Messages
1,273
Reaction score
114
Location
Prosper
When the manufacturer recommends you passivate with something like Star San, does that mean fill the entire 20g kettle? Or just maybe 4g and apply with a sponge to the rest? Just wondering if I need a big bottle of Star San.
 

Bobby_M

Vendor and Brewer
HBT Sponsor
Joined
Aug 3, 2006
Messages
24,716
Reaction score
3,374
Location
Whitehouse Station
Don't fall for the idea that starsan is an appropriate for passivation. Get some Citric acid. The ratio is 1 LB of citric acid per 2 gallons of 150F water. It should be in contact for about an hour which either means filling it all the way or running it through a CIP ball.
 

IslandLizard

Progressive Brewing
Staff member
Mod
Lifetime Supporter HBT Supporter
Joined
Jan 9, 2013
Messages
15,371
Reaction score
5,875
Location
Pasadena, MD
Don't fall for the idea that starsan is an appropriate for passivation. Get some Citric acid. The ratio is 1 LB of citric acid per 2 gallons of 150F water. It should be in contact for about an hour which either means filling it all the way or running it through a CIP ball.
Not everyone has CIP. There must be other ways, especially for larger kettles. Even for a 10 gallon kettle, that's still a lot of acid.
How about mopping the citric acid solution on, continuously, keeping the surface wet?
Or laying the kettle on its side in a trough or lay a soaked rag on the "bottom" and keep rotating?

Now the citric acid solution can be recovered and stored for reuse, but 20 gallons of it?
 
OP
P

pretzelb

Well-Known Member
Joined
Jul 8, 2009
Messages
1,273
Reaction score
114
Location
Prosper
Don't fall for the idea that starsan is an appropriate for passivation. Get some Citric acid. The ratio is 1 LB of citric acid per 2 gallons of 150F water. It should be in contact for about an hour which either means filling it all the way or running it through a CIP ball.
Since I don't have any, and I don't have CIP, that would mean 10 lbs of citric acid. Fwiw, the ones recommending Star San is As Brewtech in their instructions.
 

RPh_Guy

Bringing Sour Back
HBT Supporter
Joined
Jan 26, 2017
Messages
9,147
Reaction score
7,463
Location
Cleveland
Read this for thorough and accurate information regarding passivation:

Filing the kettle is probably the only practical way to passivate since you don't have CIP.

NO Star San.
 

Bobby_M

Vendor and Brewer
HBT Sponsor
Joined
Aug 3, 2006
Messages
24,716
Reaction score
3,374
Location
Whitehouse Station
I'm aware that SS recommends using StarSan but that won't passivate. It's not worth spending up all the starsan to be honest. Just give it a good wash out with dish soap or hot PBW. If you get any spot rusting at any of the kettle welds, hit those with Bar Keeper's Friend.
 

IslandLizard

Progressive Brewing
Staff member
Mod
Lifetime Supporter HBT Supporter
Joined
Jan 9, 2013
Messages
15,371
Reaction score
5,875
Location
Pasadena, MD
You can get 10# of Citric Acid from Alpha Chemicals for $14.50 plus (quite reasonable) shipping.
The used passivation liquid can be stored for repeated (future) use, I doubt it will go bad at that strength. I had some "white clouds" (looking like suspended cotton wool balls) form in a bottle of (odorless) photographic Stop Bath concentrate, but it still worked fine, as was the pH of the working solution. It may have been buffered somewhat.
 

RPh_Guy

Bringing Sour Back
HBT Supporter
Joined
Jan 26, 2017
Messages
9,147
Reaction score
7,463
Location
Cleveland
Do you guys successfully store your citric acid solutions for a year or more? Citric acid is a nutrient for microbes.

I don't recommend BKF in surfaces that will contact wort/beer, for reasons explained in the article linked above.
 

jimyoung

Well-Known Member
Joined
Jan 10, 2012
Messages
115
Reaction score
40
Location
Winnipeg
I'm aware that SS recommends using StarSan but that won't passivate. It's not worth spending up all the starsan to be honest. Just give it a good wash out with dish soap or hot PBW. If you get any spot rusting at any of the kettle welds, hit those with Bar Keeper's Friend.
I have a new kettle on the way and was going to use StarSan, as per instructions, to passivate.

Do you mind giving a little more instruction on why it won't work? Given that the manufacturer says we should, it'd be super helpful if you could explain why this simply won't do what we think it does... thanks!
 

RPh_Guy

Bringing Sour Back
HBT Supporter
Joined
Jan 26, 2017
Messages
9,147
Reaction score
7,463
Location
Cleveland
I have a new kettle on the way and was going to use StarSan, as per instructions, to passivate.

Do you mind giving a little more instruction on why it won't work? Given that the manufacturer says we should, it'd be super helpful if you could explain why this simply won't do what we think it does... thanks!
Check out the article. :)

 

jimyoung

Well-Known Member
Joined
Jan 10, 2012
Messages
115
Reaction score
40
Location
Winnipeg
Check out the article. :)

Apologies, I missed that. Thanks for responding!
 

day_trippr

A bad time to be an empath.
Joined
May 31, 2011
Messages
32,694
Reaction score
13,642
Location
Stow, MA
You can get a big bag of citric acid crystals from Amazon inexpensively...

Cheers!
 

jimyoung

Well-Known Member
Joined
Jan 10, 2012
Messages
115
Reaction score
40
Location
Winnipeg
Check out the article. :)

This article is great. The website also has a good article on cleaning stainless
https://modernbrewhouse.com/wiki/Cleaning

I have a SS kettle that I've always used kitchen steel wool and dish soap on... maybe I'll give it some TLC, and I certainly won't do this to my new fermenter!!
 

Gruel

Well-Known Member
Joined
Feb 16, 2020
Messages
191
Reaction score
63
Location
Chicago
I think just keeping all surfaces wet, by occasionally sloshing the citric acid around, should do it. 5% citric acid (just like lemon juice, but as somebody pointed out, if you need more than a cup then making your own 5% solution from citric acid makes sense economically) at 140F for an hour should be plenty, if I remember correctly.

And just to be clear, the citric acid removes the free iron from the surface; the actual passivation, formation of chromium oxide, happens afterwards, upon exposure to air.
 

day_trippr

A bad time to be an empath.
Joined
May 31, 2011
Messages
32,694
Reaction score
13,642
Location
Stow, MA
I found 150°F as the general recommendation.
Also, first rinse should be as mineral-free as possible, with DI recommended followed by RO water. After that any water will do...

Cheers!
 

day_trippr

A bad time to be an empath.
Joined
May 31, 2011
Messages
32,694
Reaction score
13,642
Location
Stow, MA
Jeeze, that was some time ago, but I had wandered around for over a week in spare time looking for general and then specific recommendations, and 150°F came up as the sweet spot. Some of the sites were institutional, others were SS fabricators, that much I remember.

Anyway, that's what I've been using, along with 5% CA by weight. It did an amazing job on my SS IC after I had brutalized it while threading 1/8" thick SS wire through it in three vertical runs to gap the coil (which prior was basically a 10" diameter solid cylinder). Also treated my SS spider to it (fit right inside the IC) and it looked better than new...

Cheers!
 

jimyoung

Well-Known Member
Joined
Jan 10, 2012
Messages
115
Reaction score
40
Location
Winnipeg
It's not the cheapest operation, but I will do both my kettle and new fermenter at once... so I can move the liquid back and forth, with the kettle being able to re-warm it as it cools. May try not making as much as keep it moving, but that makes me feel like it won't really work, just to save $10.

Now I just need to decide how I'll give my old kettle a nice deep clean before doing it. I have lots of OxyClean (works wonders to take pee smells out of clothes.. KIDS!!!), maybe I'll use that.
 

Gruel

Well-Known Member
Joined
Feb 16, 2020
Messages
191
Reaction score
63
Location
Chicago
This might be a good document to look at: http://www.galvanizeit.com/uploads/resources/astm-a-967.pdf

Somebody (RPH?) posted a talk from a NASA dude who didn't agree 100% with the engineers in Conshohocken (not making this up, that's the name of the town; apparently it means 'pleasant valley').

I wouldn't go overboard with this whole passivation thing; unless you have a reason to believe your equipment was machined with the wrong tools that embedded a lot of non-stainless steel in the surface of your stainless, or some weird stuff happened while welding, stainless should just passivate itself.
I like to scrub my cooking and brewing pots once in a while with lemon juice while they are still warm, just because it makes me feel good. I don't think it's strictly necessary.
Sanitizing, on the other hand, I firmly believe is.
 
Last edited:
OP
P

pretzelb

Well-Known Member
Joined
Jul 8, 2009
Messages
1,273
Reaction score
114
Location
Prosper
You can get 10# of Citric Acid from Alpha Chemicals for $14.50 plus (quite reasonable) shipping.
The used passivation liquid can be stored for repeated (future) use, I doubt it will go bad at that strength. I had some "white clouds" (looking like suspended cotton wool balls) form in a bottle of (odorless) photographic Stop Bath concentrate, but it still worked fine, as was the pH of the working solution. It may have been buffered somewhat.
Well shoot. I bought some from Amazon but at about double that price.
 

RPh_Guy

Bringing Sour Back
HBT Supporter
Joined
Jan 26, 2017
Messages
9,147
Reaction score
7,463
Location
Cleveland
This might be a good document to look at: http://www.galvanizeit.com/uploads/resources/astm-a-967.pdf

Somebody (RPH?) posted a talk from a NASA dude who didn't agree 100% with the engineers in Conshohocken (not making this up, that's the name of the town; apparently it means 'pleasant valley').

I wouldn't go overboard with this whole passivation thing; unless you have a reason to believe your equipment was machined with the wrong tools that embedded a lot of non-stainless steel in the surface of your stainless, or some weird stuff happened while welding, stainless should just passivate itself.
You might want to check out the linked article I wrote ... I reviewed not only latest version of ASTM A967 (2017), but also all the relevant literature, including multiple scientific studies looking at surface chromium percentage.
I also describe the various reasons why it can be beneficial to passivate (with numerous expert and scientific references).

What's "necessary" is simply a matter of philosophy, but hopefully this article can help people make an informed decision with regard to passivation. I have led the proverbial horse to water.
Cheers!
 

IslandLizard

Progressive Brewing
Staff member
Mod
Lifetime Supporter HBT Supporter
Joined
Jan 9, 2013
Messages
15,371
Reaction score
5,875
Location
Pasadena, MD
If you can find a large heavy mass to put in the kettle, it would reduce the amount of liquid needed to fill it.
Almost too simple, I was thinking along those same lines.
Another, somewhat smaller kettle, a large bucket or container. Heck, even a sturdy plastic bag filled with sand, gravel, or bricks, etc.
 

MikeCo

Well-Known Member
Lifetime Supporter
Joined
Sep 21, 2019
Messages
269
Reaction score
111
Location
Minneapolis, MN
That’s a good question. I wouldn’t think the acid would harm the rubber, but I’m not sure. The adhesive that holds the rubber to the stainless could be a concern too. You could try wrapping that with tape to seal the acid solution out.
 
OP
P

pretzelb

Well-Known Member
Joined
Jul 8, 2009
Messages
1,273
Reaction score
114
Location
Prosper
That’s a good question. I wouldn’t think the acid would harm the rubber, but I’m not sure. The adhesive that holds the rubber to the stainless could be a concern too. You could try wrapping that with tape to seal the acid solution out.
I was thinking I could use one of my old SS brewing pots but they have spigots on them and won't fit. I will have to see if I can get creative.
 

Bobby_M

Vendor and Brewer
HBT Sponsor
Joined
Aug 3, 2006
Messages
24,716
Reaction score
3,374
Location
Whitehouse Station
I wouldnt because it will dissolve the copper brazing and the plates are super thin. I use caustic on plate chillers because its usually clogged with organics.
 
OP
P

pretzelb

Well-Known Member
Joined
Jul 8, 2009
Messages
1,273
Reaction score
114
Location
Prosper
That’s a good question. I wouldn’t think the acid would harm the rubber, but I’m not sure. The adhesive that holds the rubber to the stainless could be a concern too. You could try wrapping that with tape to seal the acid solution out.
It turns out it doesn't matter much for the near future because I'm an idiot and didn't realize my outlet is 4 prong and my new system is 3 prong. So I'm waiting on an electrician.
 

day_trippr

A bad time to be an empath.
Joined
May 31, 2011
Messages
32,694
Reaction score
13,642
Location
Stow, MA
...or someone like him?

UN9.lxHief92q9ESbTGlVw.jpg


Set your Way Back Machine to 1968 :D

Cheers!
 

RPh_Guy

Bringing Sour Back
HBT Supporter
Joined
Jan 26, 2017
Messages
9,147
Reaction score
7,463
Location
Cleveland
That’s a good question. I wouldn’t think the acid would harm the rubber, but I’m not sure. The adhesive that holds the rubber to the stainless could be a concern too. You could try wrapping that with tape to seal the acid solution out.
Citric acid doesn't harm plastics or rubber parts.
 

IslandLizard

Progressive Brewing
Staff member
Mod
Lifetime Supporter HBT Supporter
Joined
Jan 9, 2013
Messages
15,371
Reaction score
5,875
Location
Pasadena, MD
It turns out it doesn't matter much for the near future because I'm an idiot and didn't realize my outlet is 4 prong and my new system is 3 prong. So I'm waiting on an electrician.
Depending on your system, you may be able to buy or make an adapter to go from your 4-prong outlet to the 3-prong controller.
Right!

The "4th prong" is connected to a dedicated neutral wire that's bonded to ground in your main (service) panel. It's modern day code; it prevents the (bare) ground wire from carrying any current. But basically, they do the same thing.
You may be able to just change the controller's plug to a 4-prong.
 

Bilsch

Well-Known Member
Joined
May 4, 2015
Messages
1,149
Reaction score
799
You only need a 4% solution according to NASA research so that’s 302grams acid per 2 gallons and not 454gm. That should save some money. As for a way to reduce your fill volume, don’t forget to put every other bit of stainless equipment that will fit in the pot and do it at the same time. Glass blocks would also be a good filler.
 
Top