Does Salting Water Before it Boils Cause Pitting of Stainless Steel Cookware?

[Shel_B]

I have read that salting water in a stainless steel pot that hasn’t come to a boil can result in pitting, which is a form of rusting.  Does anyone know of the veracity of this statement?

[Porthos]

I have not experienced this. Of course there are many alloys that exist under the general class of stainless steel so it would be nigh impossible to make a blanket statement like that. I can offer one specific data point. I have a Revere 3 qt S/S saucepan that my DW and I have owned for 35 years in which I have boiled countless batches of pasta in salted water (salted when started) and nary a pit. Although I was working on the electronics end of corrosion monitoring I spent 16 years in that field and my memory is that the mechanisms for pitting would be difficult to achieve in simple low-concentration salted water. If I am recalling incorrectly, that is my bad. I also still have the 3 qt S/S saucepan that my mother owned from before I was born (I'm 60) and it shows no signs of pitting either. YMMV.

 

Edited to fix a grammar error.

Edited April 1, 2014 by Porthos (log)

[Edward J]

I can verify this.  Not only with s/s but all kinds of cookware.  It's the action of heat, undissolved salt and metal.  My Mom used to have a set of s/s cookware with a spiral pattern of pitting on the inside--to match the spiral of her electric range element.

 

Many cookware mnfctrs will include some kind of literature about this pitting in thier packaging.

 

S/S is not bombproof.  One place I worked at had a s/s drawer that was divided into 1/9th s/s inserts full of pickles, cornichons, etc.  The inside of the drawer and the cabinet--all s/s,  had corroded to the point where metal flakes were falling into the food.  Many commercial electric meat slicers will develop deep pitting on the s/s blade and s/s sharpening equipment from tomato seeds and tomato juice if it isn't cleaned immediately

 

 

 

And finally, the "kitchen trick"...

No I know can explain this freaky occurance, but it's easy to do at home. Perhaps someone can explain.

 

-Get three dishes or bowls, one s/s, one ceramic, one aluminum, copper, or cast iron.

 

-Fill each one with a bit of tomato product--ketchup works well, as does tomato sauce.

 

-Stretch a piece/strip  of auminum foil across the bowl, ensuring it touches the ketchup and the sides of the bowl.

 

-See what happens to the foil after 4 hrs, after 8 hrs and after 12 hrs.

[paulraphael]

It's called galvanic corrosion. It's real, but shouldn't come up too often with cookware. 

 

Edward's experiment is explained in the wiki article ... scroll down to "lasagne cell." There are other ways salt can attack stainless stell (anyone who's rock climbed on sea cliffs knows about chloride stress corossion). The most likely issue for cookware is if salt or a strong salt solution is left in contact with the pan for a long time. This won't happen in cooking, but needless to say, don't brine a turkey in a stainless stock pot. And clean your pans well after use.

 

Several of the acids present in food (including citric, acetic, etc.) can similarly pit the 300 series stainless steels used in cookware. But these also need a lot of time. It won't happen unless you're careless.

 

The most corrosive thing in the kitchen for these metals is chlorine bleach. I don't use it around stainless steel at all. I scrub pans with BKF (oxalic acid = good for stainless), and sanitize with quaternary ammonium.

[Mjx]

Seems like the manufacturer is the one to ask about the possibility of any problems related to your question; all we can do is toss out our best hypotheses, which may be way off base, depending on the specific characteristics of the stainless steel of your cookware.

[dcarch]

There is no such thing as "stainless". They are all classified as "Stain resistant". 

 

Actually, it is more accurate to call metals "corrosion resistant" or "rust resistant". I am not sure how you can easily stain metals. You can anodize aluminum or "blue-ing" or " parkerizing" gun metal, using various methods. 

 

I am not sure regular table salt (sodium chloride) can have any effect on normal stainless steel, regardless of concentration and (kitchen) temperature. I am not sure in the kitchen you can find another metal which has more negative electrochemical potential to cause galvanic corrosion to chromium (stainless steel).

 

In the manufacturing industry, stainless steel tanks are use to transport and cook the most corrosive chemicals. I have been cooking tons of tomatoes to make tomato sauce every year for centuries, never have I found any pitting on my stainless steel cookware.

 

In the kitchen, aluminum cookware pits very easily, but not typical stainless steel cookware. 

 

dcarch

 

 

[Shel_B]

The most corrosive thing in the kitchen for these metals is chlorine bleach. I don't use it around stainless steel at all. I scrub pans with BKF (oxalic acid = good for stainless), and sanitize with quaternary ammonium.

 

What is "quaternary ammonium?"

[Shel_B]

Seems like the manufacturer is the one to ask about the possibility of any problems related to your question; all we can do is toss out our best hypotheses, which may be way off base, depending on the specific characteristics of the stainless steel of your cookware.

 

It's not an issue for me. The question was just general, with, perhaps, the idea of sharing the info with some friends who cook.

 

BTW, do you have a background in the corporate world?

[Edward J]

 

I am not sure regular table salt (sodium chloride) can have any effect on normal stainless steel, regardless of concentration and (kitchen) temperature. I am not sure in the kitchen you can find another metal which has more negative electrochemical potential to cause galvanic corrosion to chromium (stainless steel).

 

In the manufacturing industry, stainless steel tanks are use to transport and cook the most corrosive chemicals. I have been cooking tons of tomatoes to make tomato sauce every year for centuries, never have I found any pitting on my stainless steel cookware.

 

In the kitchen, aluminum cookware pits very easily, but not typical stainless steel cookware. 

 

dcarch

 

 

Please, pretty please.  Go to a dollar store or Ikea and pick up a cheap s/s pot.  Fill it half full with tepid water and thow in a good tablespoon of salt.  THEN set it on a burner, turn on the heat, and obsereve.  Then report.

 

I do agre with s/s not being "stainless"  I have had metalurgists (sp?) tell me that s/s is "Stain - less" but not stain free.

 

I also agree with aluminum cookware pitting very easy.  It also warps faster than than the USS "Enterprise"

[Shel_B]

The All-Clad FAQ http://www.all-clad.com/Pages/Customer%20Service/faqs.aspx says:

 

Stainless Steel - Salt Damage:

​To avoid the formation of small white dots or pits, bring liquids to a boil before adding salt, then stir well. Or, add salt after food has started to cook. Pitting does not interfere with cooking performance but can diminish the beauty of the stainless steel.

 

From the on-line user manual: 

Add salt to water only after it has come to the boil (to avoid salt grains attacking the steel). 

 

 

I guess I found the answer to my own question.  Didn't think to check the All-Clad FAQ - heck, didn't even know there was one.

Edited April 1, 2014 by Shel_B (log)

[paulraphael]

Table salt is definitely corrosive, even to the highest grades of stainless used in cookware. It's just that normal cooking doesn't present the kinds of conditions where this will happen. I'm not totally convinced that throwing salt into a pot of cold water will cause pitting. Maybe if the salt sits for a really long time before dissolving completely? I'm not going to test it. My stainless lined pans that are over 10 years old have a couple of little pits here and there, but these could just as easily be from someone jamming a fork into them when I wasn't looking.

 

The most important rule of thumb is not to use the pan as a storage container in the fridge, especially for anything acidic. And definitely don't brine anything in it.

 

If you need a pan surface that's completely inert, it's hard to beat enamel. My enameled iron dutch oven is the only piece of cookware that goes from stove to fridge.

[Shel_B]

I'm not totally convinced that throwing salt into a pot of cold water will cause pitting.

 

[...]

 

The most important rule of thumb is not to use the pan as a storage container in the fridge, especially for anything acidic. And definitely don't brine anything in it.

 

All-Clad makes that point about storage as well.

 

You say that brining in stainless is not a good idea, yet you feel it may be OK to put salt into a pot of cold water.  It seems that the two things are pretty much the same thing.  Why is one alright and the other not? 

[dcarch]

Please, pretty please.  Go to a dollar store or Ikea and pick up a cheap s/s pot.  Fill it half full with tepid water and thow in a good tablespoon of salt.  THEN set it on a burner, turn on the heat, and obsereve.  Then report.

 

I do agre with s/s not being "stainless"  I have had metalurgists (sp?) tell me that s/s is "Stain - less" but not stain free.

 

I also agree with aluminum cookware pitting very easy.  It also warps faster than than the USS "Enterprise"

 

We are talking about normal kitchen use, and normal general quality SS cookware, not $0.99 cheap SS cookware. Normal cookware SS is 18/10 stainless, or something close to that. Chromium and nickel are  very expensive metals, cheap cookware will not give you enough of those metals to be qualified as stainless.

 

I have done many times with salt "tests", as many people also have. I have made salt baked chicken and salt baked fish in my SS cookware many many times with no sign of pitting.

 

Don't forget, stainless steel is used extensively in marine salt water environment.

 

Your observation of the bottom of a pan with stain (rainbow stain) which coincides with the burner geometry is of a totally different phenomenon. It has to do with the thicker chromium oxide causing interference with incident light waves (partial Newton Rings).

 

dcarch

Edited April 1, 2014 by dcarch (log)

[Porthos]

For what it is worth, I stir the pot after adding the oil and salt to the room temperature water.

[paulraphael]

All-Clad makes that point about storage as well.

 

You say that brining in stainless is not a good idea, yet you feel it may be OK to put salt into a pot of cold water.  It seems that the two things are pretty much the same thing.  Why is one alright and the other not? 

 

The difference is that people brine things for periods of many days. Pitting is a progressive process ... it starts with surface oxidation that protects stainless steel breaking down, so the chlorides can get to the base metal. This takes a lot more time than it takes to make pasta.

[paulraphael]

Don't forget, stainless steel is used extensively in marine salt water environment.

 

 

It also corrodes in a marine environment. Stainless hardware on ships needs less maintenance than regular steel, but it needs maintenance. And there are situations in a marine environment where stainless steel is specifically not allowed, because it's especially vulnerable. 

[annabelle]

I have several sets of pots and pans:  cast iron, All-Clad and heavy cast aluminum with copper cores that I have had for 35+ years.  I always add salt to water before I put it on to boil and have no pits or stains in any of my pots or pans.

 

I cook every day, some times multiple times in a day as well as doing a lot of canning in the late summer and fall.  Years of heavy use and experience have shown that it's pretty damned hard to damage a decent pot or pan.

[Edward J]

We are talking about normal kitchen use, and normal general quality SS cookware, not $0.99 cheap SS cookware. Normal cookware SS is 18/10 stainless, or something close to that. Chromium and nickel are  very expensive metals, cheap cookware will not give you enough of those metals to be qualified as stainless.

 

I have done many times with salt "tests", as many people also have. I have made salt baked chicken and salt baked fish in my SS cookware many many times with no sign of pitting.

 

Don't forget, stainless steel is used extensively in marine salt water environment.

 

Your observation of the bottom of a pan with stain (rainbow stain) which coincides with the burner geometry is of a totally different phenomenon. It has to do with the thicker chromium oxide causing interference with incident light waves (partial Newton Rings).

 

dcarch

 

Yeah, I know, still unwilling to do a simple test.  Maybe if I mail you a couple of bucks so you can buy the s/s cookware and try it yourself?

 

There's a lot of theory and scientific data to prove that a bumblebee can't fly, but it does. 

 

Read some of the posts by others who've copied and pasted information from high quality s/s cookware manufacturers about undissolved salt, heat, and metal, hey maybe they're wrong too.

 

And for what it's worth, in my original post I wrote nothing about rainbow stains. I specifically wrote a spiral pattern of pitting that matches the spiral pattern of the electric element on my Mom's stove. 

 

Not only does s/s corrode in marine enviroments, s/s is used in hvac systems and it corrodes as well.

[paulraphael]

One of the benefits of a cleaner like barkeeper's friend is that its oxalic acid re-passivates stainless steel. This means that if a corrosion process has begun (which means the protective, passive layer of oxides has been broken down), the cleaner will restore the protection to its original state. Some other kinds of cleaners, like ones with strong abrasives, chlorine bleach, or ferrous metals (steel wool) will make things worse.

[dcarch]

Yeah, I know, still unwilling to do a simple test.  Maybe if I mail you a couple of bucks so you can buy the s/s cookware and try it yourself?

 

Thank you for your generosity. As I said, I have done enough tests already, and as I said a two buck SS cookware is not a SS cookware.

 

There's a lot of theory and scientific data to prove that a bumblebee can't fly, but it does. 

 

Of course you are free to believe those "scientific" data, which contradicts reality.

 

Read some of the posts by others who've copied and pasted information from high quality s/s cookware manufacturers about undissolved salt, heat, and metal, hey maybe they're wrong too.

 

They are not wrong. I never said they are wrong.

 

And for what it's worth, in my original post I wrote nothing about rainbow stains. I specifically wrote a spiral pattern of pitting that matches the spiral pattern of the electric element on my Mom's stove. 

 

That's why I put "rainbow stain" in parentheses. You may want to Google "stainless steel, rainbow stain".

 

Not only does s/s corrode in marine enviroments, s/s is used in hvac systems and it corrodes as well.

 

I said, "---stainless steel is used extensively in marine salt water environment." Do you agree? As far as I know, in HVAC systems, galvanized steel is used mostly in ductwork, copper is used in piping, aluminum is used in fin tube fins, and vinyl tubing is used in some control lines. I am not sure, in common HVAC system that SS is commonly used.

 

To be on topic, salt in general and in common kitchen use environment, is unusual that it can pit a normal quality SS cookware.

 

dcarch

[KennethT]

My mother's All-Clad LTD stockpot has some minor pitting on the bottom. Quite a while ago, I wondered how it happened, so without telling her and without her realizing that I was watching carefully, I observed how she prepared the water for boiling pasta or vegetables. She'd take cold water out of the tap, put it on the burner, turn it on, then immediately dump (literally) in a bunch of kosher salt. The kosher salt stayed largely undissolved on the bottom of the pot, even as the water heated up and came to a boil. At one point, while boiling, I took a wooden spoon and scraped the bottom and found a lot of salt "welded" to the bottom, which would come off with quite a bit of scraping. The reason why they recommend adding the salt to the water when boiling is that, chances are, it dissolves before it gets a chance to collect on the bottom of the pot. No matter how salty you make your water, salinity at that level for short periods of time will not harm s/s... but imagine the microconcentration of salt at the point of where the clump is welded to the bottom!

[Edward J]

I am not sure regular table salt (sodium chloride) can have any effect on normal stainless steel, regardless of concentration and (kitchen) temperature. I am not sure in the kitchen you can find another metal which has more negative electrochemical potential to cause galvanic corrosion to chromium (stainless steel).

 

 

Well, then do the experiment as described above for yourself.  Many other posters have described this, or quoted from well known cookware manufacturer's websites on avoiding it.

 

We're still waiting for you do do simple experiments with cooling down stock in water baths, and experiments if refrigeration uses less electricity  to maintain cabinet tempertaure when fully loaded vs. totally empty.

 

I know, I know, it's just eaier to argue moot points than it  is to actually do the simple test.  Hey, the Germans call stainless steel  "Rostfrie",  or "rust free".

[JohnT]

Pure stainless steel should not pit with the addition of salt in your water, irrelevant of which stage it is added. The problem with pitting is that in the modern time we live in, a lot of so called stainless steel is so cheaply manufactured that it contains impurities of iron and other metals which pit (corrode) through galvanic action. A lot of the nice shiny new stainless steel pots and cookware coming out of China is absolute junk with huge amounts of impurities in the stainless steel. If you use these on an electric range, they may also be affected by electrolysis from stray electrical currents which would not be of an issue when cooking on a gas (propane / butane) range.

In the marine industry we use 316 stainless steel for above water fittings. A few years ago the Vietnamese and Chinese entered the supply chain and boat yards thought it a good idea to buy these as they were around 25% cheaper. The exercise turned out to be an expensive one as the stainless steel had so much impurities in it that they started to corrode as soon as the vessel was in the water.

What I am trying to convey is the message that a lot of the so called stainless steel cookware available is not pure and the impurities will leach out during cooking. Even the common thin walled stainless steel mixing bowls found everywhere these days will start pitting the moment you add any acidic food. I still have a few battered stainless steel pots I inherited from my father that were manufactured in Germany. They must be over 50 years old and show no sign of pitting. However, I purchased a few heavy duty stainless steel pots (made in China) about five years ago. They do stain and show slight pitting already. I doubt they will even last 25 years before having to be replaced. Basically, most cookware ain't made like it used to be.

John.

[fvandrog]

Basically, most cookware ain't made like it used to be.

 

With the higher end cooking ware, which I assume any eGullet participants use (or aspire to using) I think you are pretty safe. It's the low- to mid-range cooking ware that seems to be of rather disappointing quality. I'd like to be able to say that you get what you pay for, but I have the general impression that event that's not the case.

[paulraphael]

Pure stainless steel should not pit with the addition of salt in your water, irrelevant of which stage it is added. The problem with pitting is that in the modern time we live in, a lot of so called stainless steel is so cheaply manufactured that it contains impurities of iron and other metals which pit (corrode) through galvanic action. A lot of the nice shiny new stainless steel pots and cookware coming out of China is absolute junk with huge amounts of impurities in the stainless steel. If you use these on an electric range, they may also be affected by electrolysis from stray electrical currents which would not be of an issue when cooking on a gas (propane / butane) range.

 

Do you have any sources on this? Articles I've read mention nothing about impurities being a primary issue here ... just the fact that many chemicals are capable of removing the passivation layer that forms to protect all stainless steels. Did you see the article I linked above?

 

I'm confused by the phrase "impurities of iron and other metals ...", when 300 series stainless steels are over 70% iron by composition. In steel metallurgy, the typical impurities are sulfur and phosphorus and other trace elements. These are a bigger deal in knife steels than in pots 'n pans.