The short answer is that not all stainless steel is made the same way, and as a result some is considered safer than others. Craig Stellpflug, who is identified as a cancer nutrition expert, explains that “Stainless steel cookware is made from a metal alloy consisting of mostly iron and chromium along with differing percentages of molybdenum, nickel, titanium, copper and vanadium. But even stainless steel allows other metals to leach into the foods. The principal elements in stainless that can have negative effects on our health are iron, chromium and nickel.”
When you look at stainless steel cookware, you’ll see numbers such as 18/0 and 18/8 that refer to the percentages of chromium and nickel in the stainless steel alloy. The “18” refers to the chromium content, which gives flatware its rust-resistance properties, and the “8” or “10” refers to the nickel content, which gives it its silver-like shine and some rust-resistance. 18/8 and 18/10 are the most common types used for stainless steel cookware and food applications. According to the National Institute of Health (NIH), safe dietary intake of chromium for adults and adolescents is 25 to 45 μg per day. However, there is no Tolerable Upper Intake Level (UL) set . The chromium in solid stainless is not to be confused with Chromium 6. Chromium 6 (hexavalent chromium) is a carcinogen that is given off in fumes during the welding of stainless steel, but our kitchen stoves cannot cause stainless steel to break down to this level.
As John Moody points out “… the health risks from the nickel are worse than from the chromium. For this reason, it is best to stick with higher chromium stainless steel cookware. Our body needs chromium albeit in small amounts. There are also many biological defenses against excess intake.”
According to numerous sources, the safest stainless steel to cook with is nickel free or 18/0. The outside layer of Gunter Wilhelm cookware is made from type 430 stainless steel. This kind of stainless steel material contains a minute amount of nickel (0.50 percent or less). Also Homichef makes a food grade nickel free stainless steel (21/0) which is labeled as non-toxic, and non-allergic. The 6-piece set I link to is sold on Amazon at a 37% discount.
Update – I had a follow up question that prompted me to add this information: Ted Mooney explains that the differences between 18/10, 316, 316L, and 316Ti are subtle and minor. Saladmaster is made from 316Ti, which still contains nickel. Also, I just found another couple more cookware options that are 18/0: Jarhill and Faberware. I spoke to a representative at Faberware and he said that the current products are 18/0 stainless steel. No nickel. So it depends on what version you have. Look on the outside botton of your pot. If it says 18/0 or durable, there is no nickel, otherwise it will either say 18/10 or aluminum clad and that would pertain to the older products that do contain nickel. So in summary:
Non-Nickel Stainless Steel Cookware:
Very low-nickel: Gunter Wilhelm
I also recommend glass cookware, and cover other options in my cookware recommendations article.
Another Update! September 28: I called Saladmaster today and spoke to a representative. She said they don’t share their names when I asked for hers – (817) 633-3555 Option 4. She confirmed Saladmaster does contain 16% to 18% chromium and 10% to 14% nickel, and is more stainless steel than titanium. Titanium content is typically only around 0.5%, as you’ll see in this document she emailed me. I asked her if they had any research on the product materials leaching into food and they do not. I summarized this study. She said that even with the Saladmaster, with extensive exposure to acid foods, and/or salt, prolonged use can create pitting in the metal. I explained that we recommend folks add vinegar to the bones used to make broth to draw out the minerals, and folks likely add salt as well for flavor. I said my perspective is that bone broth simmered in stainless steel for 12 to 72 hours may not be the safest cookware option. I asked her if that sounded like a reasonable statement to her and she said “yes, it does!” I personally think that the very safest way to make broth is in non-metal cookware.
I also learned more about Xtrema ceramic cookware, and see that it appears to be another safe cookware option based on this article and others I read.
When it comes to cookware, I err on the side of caution. I don’t use or recommend the Instant Pot because I am not drawn to the high heat and high pressure of the pressure cooker feature. I also would not use it as a slow cooker because the inside part is made with 18/8 stainless steel. That means that it is 8% nickel. Metals are found to leach into food cooked in stainless steel, according to research published in the Journal of Agricultural and Food Chemistry:
After a simulated cooking process, samples were analyzed by ICP-MS for Ni and Cr. After six hours of cooking, Ni and Cr concentrations in tomato sauce increased up to 26- and 7-fold respectively, depending on the grade of stainless steel. Longer cooking durations resulted in additional increases in metal leaching, where Ni concentrations increased 34 fold and Cr increased approximately 35 fold from sauces cooked without stainless steel.
Cooking with new stainless steel resulted in the largest increases. Metal leaching decreases with sequential cooking cycles and stabilized after the sixth cooking cycle, though significant metal contributions to foods were still observed. The tenth cooking cycle, resulted in an average of 88 μg [micrograms] of Ni and 86 μg of Cr leached per 126 g serving of tomato sauce. Stainless steel cookware can be an overlooked source of nickel and chromium, where the contribution is dependent on stainless steel grade, cooking time, and cookware usage.
Many in our community use the Instant Pot to make broth in. Our recommendation is to add vinegar to the broth to draw out the minerals from the bones. As John Moody asserts: “For longer cooking and acidic foods, such as tomato based sauces or slow simmering of stocks, use alternate cookware. Safe options include certified toxin free clay pots, such as Vita-Clay, glass, or ceramic coated cast iron. While convenient, stainless steel pressure cookers are not ideal for cooking these items.”
As I said, I don’t use or recommend an Instant Pot; especially not for broth. I use a Hamilton Beach crock pot to make broth in, as well as a stainless steel stock pot that passed the stainless steel magnet test explained below. Before you ask, I am not concerned about lead in this crock pot. In addition, see this article from the Lead Safe America Foundation. I also use a Le Creuset stock pot for broth.
Acidic Foods and Beverages
John Moody also points out that “Bottled store kombucha, an acidic beverage, is typically brewed in large stainless steel vats. It is best to avoid commercial kombucha for this reason. Be sure to brew kombucha or Jun tea in glass or tested, toxin free ceramic when made at home. Store these beverages only in glass as well.”
How do we know if there is nickel in our stainless steel cookware? Copied from my cookware recommendations article:
Stainless Steel Magnet Test
There are two main types of stainless steel, magnetic and nonmagnetic. The nonmagnetic form has a very high nickel content, and nickel is allergenic and carcinogenic. It is much more toxic than iron or aluminum. You can use a little “refrigerator magnet” to test your pans. The magnet will stick firmly to the safer type of pan.
It is wise to use the magnet all over the pan – inside and outside since some have found that the pan contains mixed ingredients and sticks firmly in some places and not in others.
Sources: Magnet and Stainless Steel Cookware, Magnetically Attractive Stainless Steel Cookware
Scratched or Damaged Stainless Steel
Also, keep in mind that aluminum is sometimes placed in between stainless steel layers in stainless steel cookware. So if your cookware becomes scratched or damaged in any way, including rust, aluminum may leach into your meals as well. I would recommend you recycle stainless steel that may pose that risk.
36 Responses to Is Stainless Steel Cookware Safe?
Please list even a few of the sources that discuss how much better and why Gunter WIlhelm and Homichef are to Saladmaster. I am curious.
From what I learned on their website Saladmaster is made from 316Ti, which from what I’ve read is essentially the same as 18/10 in terms of the nickel content. I link to the source of that information in the post. If you have research that points to the fact that Saladmaster will not leach nickel into the food we cook, I am very open to receiving it.
Also, read Kim Schuette’s comment below: https://nourishingourchildren.org/2017/09/25/stainless-steel-cookware/#comment-15119
Saladmaster is made by Regalware. They are a “Made in USA” company. They are not a public company, but are family owned. If you go to their website (regalware.com) you will see they also have other lines of cookware: Royal Queen, Lifetime, American Kitchen, Classica & West Bend (Chinese Line). This company is only 30 miles from me & it was written up in our local paper, the Milwaukee Journal/Sentinel (see link). It’s odd to see how the Chinese are buying USA cookware & we’re buying Chinese cookware. What do they know that we don’t.
I have chosen to avoid nickel in stainless steel, and explained why. Each of us will make purchases based on our priorities and values, of course.
I don’t feel good about using pressure cookers such as the Instant Pot. Any time we use high heat and high pressure at the same time in cooking, we have to question what is happening to the molecular structure of the food. There is also the unanswered question about the levels of glutamic acid in the broth created by the pressure cooker. As a Certified GAPS practitioner, [which is the Gut and Psychology Syndrome dietary healing protocol] and as someone who works with people who have leaky gut and leaky brain barriers, its not worth the risk for me to suggest the use of pressure cooker.
Read more in this article: https://www.seleneriverpress.com/the-dark-side-of-bone-broth/
Yes, Sarah Pope of The Healthy Home Economist, has a similar perspective in her article: http://bit.ly/pressurecookerarticle
She talks about the pressure cooker problems that won’t go away: “While there are so many positives on the use of a pressure cooker and the science seems solid that using one is beneficial to the cooking process as compared with regular stovetop cooking, I still choose not to use one.
First of all, most pressure cookers that I’ve examined are made of stainless steel. The heavy metal leaching dangers of cooking acidic foods in stainless steel cookware is very real. I wanted an appliance that I could cook any food in – acidic or not. This is why I chose a Vita-Clay (I actually own two!).
Secondly, I passed on a pressure cooker because I have not found conclusive research that refutes my concern that pressure cooking may, in fact, dramatically increase the glutamine in cooked foods, most particularly the potential for MSG in bone broth.
Glutamine is a conditionally essential amino acid that is critical for gut, brain and immune health. It is found naturally in healthy foods and should theoretically not be a problem in normal metabolic situations. The problem develops when glutamine gets past the blood brain barrier and is metabolized to glutamate. In healthy individuals this process is tightly controlled by the body. Glutamine is supposed to convert as needed to either glutamate, which can excite neurons, or to GABA, which has a calming effect.
The glutamine levels in pressure cooked bone broth are as yet unknown. In addition, how pressure cooking affects the nutrients in bone broth is also up in the air. Here’s what Kaayla Daniel PhD, co-author of Nourishing Broth has to say about the affect of a pressure cooker on the nutrients in bone broth: Neither Sally nor I use a pressure cooker … in terms of nutritional value, we have not done comparison testing of pressure cooker broth vs stockpot vs slow cooker [due to the cost involved].”
As a nutritionist and Certified GAPS Practitioner (and VP of the WAPF), I appreciate this article in that it gives our community information that helps move us towards healthier options for food preparation. I am not comfortable using a pressure cooker (including the Instant Pot) due to the high heat and high pressure. I much prefer slow and low cooking. Instinctually, pressure cooking feels counter to the slow food philosophy that I have found to be so nourishing to my family over the past three decades. When doubt exists, prudent avoidance is my default. So, it’s easy not to use a pressure cooker (just like never using a microwave) in light of the unanswered concerns I have.
Regarding nickel exposure from most stainless steel cookware, again, I prefer to avoid the addition of inorganic nickel to our food. Naturally occurring (organic) nickel exists in certain foods and for individuals with nickel allergies or estrogen dominance, these foods should also be avoided. For the rest of us, avoiding leaching inorganic nickel into our foods from using nickel-containing cookware is always a best choice.
I suggest people start by purchasing one large nickel-free skillet and then budget to replace other pieces over a realistic time frame. Most of us can get away with far fewer pots and pans than we think. As with everything, we each do what we can and above all keep calm and add butter!
I am still using the old Farberware I bought in my twenties, almost 50 years ago. I read that nickel diminishes with time but I can’t find the source. Is that true? And if so, maybe my beloved skillet and sauce pans are nickel free by now.
Thank you Sandrine! I’ve had to turn down the gift of an Instant Pot several times because I personally don’t think super high heat and pressure is a nutritious way to cook. But I didn’t think of that metal in it. Thank you!
Sandrine, This isn’t the same topic, but it’s related, in my mind. I’ve been pondering sardines and wondering what is a good brand to purchase. They are canned, and I typically don’t eat canned food; but I’d like to get the benefits of sardines, and my child loves them. So I’d like to find the best option for getting sardines without the downside of the chemical linings of the cans. Have you found any such option? I believe some linings are better than others, but haven’t yet located sardines in a better-lining option…though I haven’t done an exhaustive search. Are there any you can recommend? I ponder this question with all fish, really, not just canned fish. Even the non-canned variety comes in plastic packaging. The cans are very convenient for simple lunches, good to have on hand for emergency preparedness, etc. So I don’t want to eliminate it completely, but would like to have an option I feel good about.
Hi Tara, I wrote this post on sardines, and recommend and order Vital Choice seafood! http://bit.ly/sardinesalad
Wild Planet is another good brand. I have corresponded with them b/c they also sell white anchovies which are just delicious and milder than sardines. They assured me their can liners have absolutely no BPA. But b/c BPA is ubiquitous now, they took “BPA free” off their labels b/c when they test sometimes they find small amounts IN THE FISH themselves (not from the can) b/c the worlds oceans are now contaminated. They assured me this would be the case with any enlightened brand regardless of label claims. The CS rep was so responsive and provided more information than I requested.
By the way, I wanted to let you know that the links for the Gunter Wilhelm cookware in your article go to a different brand. I did find a couple of options by searching for Gunter Wilhelm on Amazon, but they are different than what is shown in your links.
Thank you so much for alerting me to this error! The Gunter Wilhelm Stainless 300 series is a 5 ply construction, which is full-clad. 430 induction ready stainless, followed by a 3 layer aluminum core, finished with 430 surgical stainless electropolished to a mirror finish.
Thanks for another excellent post! Reminds me that I need to make a few changes in the kitchen.
I was curious about the metals myself but it’s my understanding that the instant pot uses high pressure but not high heat. https://wellnessmama.com/77757/pressure-cooker-nutrients/ I basically never cite things as fact anymore because the realities of everything we are educated on is ever changing. Thanks for this in depth information!
I am also wondering about drinking from stainless steel. its not heated, so is it harmless?
I don’t use stainless steel water bottles, personally. I prefer glass. I use glass with a silicone padding.
[…] to cook, and use my kitchen stuff very regularly. My mother in love did some research and sent me this informative blog. Read it. You can simply perform a magnet test on your current […]
Thank you for this article, much appreciated!
You are most welcome, Greg!
I recently purchased some Homichef cookware and find it to be very well made. Also I noticed on tigerchef.com that they mention 18/0 stainless steel in the description for Crestware pots and pans, which appear to be inexpensive models for the food service industry.
Thanks for the feedback, Greg! I will take a look!
I recently purchased a Crestware 20 quart stockpot through amazon.com and it looks to be nickel free. It came in a box labeled 18/0 stainless steel. A magnet will attach to the lid, sides, and bottom of the stockpot which is consistent with ferritic class type 430 (18% chromium, 0% nickel) stainless steel.
I grew up with an enameled Silit pressure cooker in Germany. And I just found out that I can get an enamled Silit pressure cooker here in the US. Many times I use my pressure cooker pot just for regular cooking like a dutch oven. And this one is induction capable, which is awesome. I don’t cook bone broth (family demands vegetarian food) but as far as the chemistry of pressure cooking, my views pretty much align with hers: https://www.foodrenegade.com/pressure-cooking-healthy/
I don’t use a pressure cooker as I favor low heat and low pressure cooking. We are empowered to decide for ourselves!
I find the comments about salad master interesting because I have just researched that product and my findings conclude that the 316ti is one of few metals that do not leach metal. That is why only 316ti is used surgically. And the 316ti salad master uses is Swiss made and does not have any other metal contaminates as it is pure. So while there is Nickel, it is sealed in with the titanium and does not leach out. Many 18/10 304’s or even 18/0 leach metals and toxic heavy metals that are hidden in the pans due to a low quality metal being used (impure). This can be easily verified with the “baking soda test”. So when performing the baking soda test I could taste the metals that leached out of all my other cookware except the salad master 316ti that I tested. I encourage you to test this yourself.
Thank you for your feedback! I’ll look up the “baking soda test”!
Thank you for this informative discussion What is the baking soda test?
Chantal Cookware (chantal.com) also makes a beautiful line of 21/0 stainless steel cookware. They also have their original enamel-on-carbon steel that has a glass like enamel surface that is completely non-porous and available in Cobalt Blue and Fade Grey.
I can add one more nickel free cookware it is
SOLIDTEKNICS nöni. Very good feedbacks.
I called the YETI manufacturers because I just purchased a 64 ounce stainless beverage
container they made. I was told not to put hot soups in it (because they may cool down and
explode the top), but it was fine for tea or coffee or for cold beverages (yet these specifics were not listed on the product). I was also told the metal was 18/8 stainless/nickel. If I keep it– I will rinse it out several times with hot water and soap. Stainless is a good insulator for cold beverages but I prefer
a glass water bottle for smaller quantities.
thanks for a great article! I’m in the market for new pots and pans and love the idea of stainless steel. I found this one and it’s made in the US.
Hello. Are crock pots safe? We like to do slow, low heat cooking. Thank you for this great web-site.
Yes, we recommend that you check that they are lead-free!