In a previous post I mentioned that stainless steel can leach aluminum. I was really surprised at the amount of questions and comments that generated!
I had read that leaching from stainless steel cookware might be a significant issue if you are attempting to heal a sensitive person (like my daughter who has been on GAPS for over 2 years), but honestly I have never really tackled the issue in my kitchen. Those big pots are expensive, and the ones I own are average quality.
Now, after over 2 years on GAPS my stock pots are starting to pit and look a bit worn, and I am feeling a little bit uneasy about the amount of broth we are cooking in them. It's time to invest in some new ones and to do a little more learning.
What is stainless steel?
Stainless steel is actually a low carbon, iron-based steel which has other metals mixed in to increase its corrosion resistance and strength. It always contains at least 10% chromium. Other metals can include nickel, manganese, aluminum, silicon, and sulphur. The combination of metals determines the grade of the stainless steel.
Cookware With a Core
Stainless steel does not conduct heat well, so cookware is usually made with an aluminum or copper core. A sheet of aluminum or copper sandwiched between the stainless steel improves the pot’s heating ability.
The aluminum or copper core only becomes an issue if the pot is scratched, grooved, or worn to expose it. If your pot is rusting or if there are signs that the core is wearing through, it is time to replace the pot because it’s probably leaching those metals into your food.
What are those numbers on the bottom?
Those numbers you see on the bottom of your pot are actually a clue to the grade of stainless steel. These numbers specifically refer to the amount of chromium and nickel blended into the stainless steel. For example, the numbers 18/10 show that the pot is comprised of 18% chromium, and 10% nickel.
The grade of stainless steel identifies how corrosive it is. 18/8 and 18/10 indicate that the pot is part of the 300 series of stainless steel. With a higher amount of nickel, the 300 series is more resistant to corrosion and rust. A pot stamped 18/0 is part of the 400 series. With less nickel, these pots are more vulnerable to corrosion; they are also magnetic. 200 series stainless steel is considered low quality and made with manganese instead of nickel.
Leaching and Choices
Through normal wear and tear, the metals in stainless steel will leach into food. Cooking acidic foods will cause the pot to leach higher amounts. In general, nickel leaches in higher amounts than the other metals.
Knowing that all stainless steel leaches to some degree means that when cooking for a particularly sensitive or compromised individual, quality enamelware or ceramic cookware may be a better choice. Especially if you are cooking large amounts of broth and soup for healing purposes. If you have a nickel allergy you may need to avoid stainless steel entirely.
When shopping for stainless steel cookware, try to avoid the 200 series. It corrodes easily, is not durable, and contains manganese which can be extremely toxic. The 300 series is the most common and the considered the most durable. It is also highest in nickel.
Even though the 400 series is said to be less durable, it's small amount of nickel makes it the safest choice.
As with anything else, it is best to check the country of origin of your cookware. Imported cookware will be made from metals sourced, heated and poured under different regulations. If you are purchasing cookware from a country outside of the U.S., it would be best to research the specific manufacturing guidelines of that country. An informed decision is always a safer one.
The decision on whether or not to use stainless steel is completely individual. We can’t all afford the fancy cookware, and we may not all need it. My home has experienced significant healing while cooking massive amounts of broth in 300 series stainless steel stock pots. But now that they are beginning to wear, I think it is time to replace them with something a little safer.
Do you already have a favorite stainless steel cookware brand? Or do you use something else for your stove top? I'm not sure yet what I will choose to replace my worn pots. Let me know your recommendations in the comments.
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