Nowadays, more and more concerns arise about some commonly used cookware types, and stainless steel is a good example.
It is well known that nonstick cookware can become unsafe when overheated. This is one of the reasons why many people started to search for safer alternatives like stainless steel.
However, even though stainless steel cookware is well known for its inertness in interaction with food and its corrosion resistance, someone could question If it is safe when heated up?
In general food grade, stainless steel is safe to use till temperatures between 800 and 900C, while its melting point is more than 1300C. This makes it safe for most of the common kitchen applications and it applies to commonly used food grades of stainless steel such as 304 and 316.
However, some additional questions can arise around this topic. Does stainless steel give off toxic fumes when heated? Does the use of Stainless steel on high heat constantly lead to warping or damaging your cookware?
In case you have the same questions, continue reading the text so you will be able to find some publications that I summarized around this topic. Moreover, I will share some of the impressions from my personal experience, after using stainless steel cookware for years.
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1. Is stainless steel safe when heated?
Stainless steel is an alloy of iron that has an addition of chromium and nickel. In common stainless steel food grade 304 the mass percentage of chromium is 18–20% while the nickel count for 8–12% (1).
Chromium plays the role of the main alloying element and it improves the stainless steel’s corrosion resistance by forming a transparent chromium-oxide protective film on the surface(2). The increase of the chromium content increase also the corrosion resistance.
In addition, when it comes to the temperature resistance of food-grade stainless steel a few facts could be highlighted. AZO Materials, the leading online publication platform for the Materials Science community provided the following information about 304-grade of stainless steel heat resistance(find it in their information sheet).
...good oxidation resistance in intermittent service to 870 °C and in continuous service to 925 °C.
However, they added up that:
Continuous use of 304 in the 425-860 °C range is not recommended if subsequent aqueous corrosion resistance is important.
Saying in the other words, 304 alloys can be used up to temperatures of more than 800C(1470F) for a short time without the risk of stainless steel corrosion damage from water and moisture. However, for Longer use temperatures up to 425C(800F) are recommended, which is perfectly aligned with all of the common cooking practices.
Apart from stainless steel grade 304 other SS alloys are used for the kitchen. A common example can be grade 316 stainless which contains between 2% and 3% molybdenum, which increases resistance to corrosion, acidic elements, and high temperatures even more compared to 304 SS grade(316 and 304 are in general two most commonly used grades of stainless steel when it comes to cookware and cutlery).
Finally, to demonstrate the resistance of stainless steel to high temperatures, it is good to consider the melting points that are higher than a thousand degrees. As indicated by the British stainless steel association 304 stainless steel, the alloy reaches its melting point at the 1400 C – 1450 C(2550-2640F) range(3.)
All of the mentioned declares the food grade Stainless steel suitable for temperature ranges used in all common kitchen applications(Up to around 400C/750F).
However, even if the steel stays resistant to corrosion, other potential questions can arise about the safety of its use in high cooking temperatures. I will summarize some important information on that in a few upcoming subheadings.
2. Does stainless steel produce toxic fumes when heated?
Many of us have heard about the concerns about using non-stick cookware on high-heating setups.
And this is closely related to the organic nature of nonstick coatings that are applied with Teflon-based non-stick cookware.
Organic molecules from which Teflon is made react with oxygen and break down into the different components that form fumes (4.). I deeply go into this topic of Teflon degradation concerns in my post about Granite cookware which is also commonly made from Teflon coating(Also known as PTFE), with the addition of color patterns. There I have summarized different scientific studies on this topic.
However, The question of does stainless steel give off toxic fumes when heated also arises.
As a general rule, stainless steel cookware doesn’t release toxic fumes when heated. When stainless steel cookware is exposed to high heat it forms an oxidized protective layer which contributes to even greater inertness and stability of the cookware surface.
Unlike organic coating present in some nonstick pans(like Teflon cookware), metals do not break down into volatile components in the presence of oxygen.
The Nickel Institute, one of the leading experts in the field of the application of nickel in stainless steel, stated about this topic:
Chromium is the principal alloying element that imparts to stainless steels their corrosion-resistance qualities by combining with oxygen to form a thin, transparent chromium-oxide protective film on the surface.
So it seems quite clear that stainless steel is not releasing toxic fumes when exposed to high heat. However, another common question arises over the safety of SS use in the kitchen, and that is that leaking to food.
In this article, I have summarised the opinions of Food Safety authorities on that topic and provided you with all you need to know in one post so you don’t need to search for endless other articles to fill the gaps in the information.
3. Can cooking with stainless steel on high heat damage my cookware?
Using high heat with the stainless steel during cooking is desired practice since it makes it nonstick. This is why you usually want to preheat your stainless steel pan before adding any food(In this post I described step by step how to preheat your stainless steel during cooking, and why preheating makes this material nonstick)
So heating the stainless steel is not the problem. However, What is important is how you heat the stainless steel cookware. Like with any other cookware, when using stainless steel utensils on a cooktop, it is important to apply the stove equal to or larger than the cookware bottom.
If you heat the SS cookware pieces on the stovetop smaller than its bottom surface this will cause concentrated exposure to the heat in one place. Additionally, doesn’t matter how well certain cookware pieces spread the heat, the parts of the utensil bottom that are not in contact with the heated stove will be a lover in temperature.
Finally, heating leads to the expansion of the material, especially when it comes to metal. Consequently, non-equal heating up of the bottom surface (if e.g. stovetop is smaller than the bottom and it focuses the heat just to one bottom part) leads to the unequal expansion of the patrial and finally warping.
*An example of warping beginnings in one of the old pans that I was able to find in my family house
In the last year or so, I have sometimes used some of my 12-inch stainless steel pans on smaller stovetops. However, if you do this only a few times in hundred times of cooking and you use high-quality cookware it should not be a problem. However, if you practice this on a weekly bases, expect that warping will occur.
Finally, one thing that you would like to avoid is exposing stainless steel to extreme temperature changes. This includes avoiding practices like putting your pan directly in the water after cooking.
Unfortunately, I see many people doing this. Additionally, many people believe that if you use hot water to rinse a hot stainless steel pan after cooking it should be ok.
However, the pan temperatures during cooking are usually higher than 100C/212 F and they are commonly heated up to 150-200C/300-390 F (I know this from personal experience since I frequently use an IC thermometer)
However, the temperature of hot tap water is rarely over 50-60C/120-140F, which can lead to temperature shock as big as 100C/212F or even higher.
4. Additional words
Stainless steel cookware was one of the first utensils that I got when I started my steps in the kitchen
I have found them very versatile, and I commonly recommend them to people who want to switch from the Nonstick cookware
I have been using many stainless steel utensils in the last few years. Moreover, I am looking forward to sharing with you some of the in-depth reviews of some stainless steel cookware pieces that I use weekly so you may find some useful directions if you are searching for stainless steel cookware.
Recent examples can be a review of my 12-inch stainless steel skillets from Misen and Sardel, which I put under the test for more than half a year.
