Last week on my radio show I was asked whether cheaper brand cast iron saucepans might contain lead?
It’s quite a common question – there are also websites where people asked this question, which is no doubt the source of the listeners query. It appears to be based on the fact that often when people pick up cast-iron saucepans they feel particularly heavy – they therefore wonder whether the increased weight might be caused by lead.
As it happens, this fear is ungrounded. Cast-iron saucepans will not contain any lead.
Here’s why:
Cast iron saucepans, as the name suggests, are made by being “cast” into a mould. The iron must therefore be heated hot enough not only to melt it, but hot enough so that there is time to pour it into the mould before it starts to cool and solidify. It is therefore heated substantially hotter than its actual melting point.
The melting point of iron is 1,535° C.
To cast it, they would therefore heat it no doubt several hundred degrees past this temperature.
Now, let’s look at lead. Lead melts at a mere 327.5 °C and by the time you reach the melting point of iron is very close to its actual boiling point of 1,750°C
So when the lion is hot enough to be cast, it would actually be above the boiling point of lead. So what little lead there may be in the iron, would simply boil out of it before it was cast, in exactly the same way that when you use beer or red wine in a recipe, the alcohol all boils out very quickly and you are left with the taste of the wine, but not the alcohol.
But there is one word of caution here. In years gone by lead was used as a pigment in paints. It is possible that very old saucepans with enamel coatings may have lead in their pigment. But most cast-iron saucepans are bare cast-iron, so this is not a problem.
So why do are people have this impression that cast iron feels “heavier” than stainless steel saucepans? The reason simply is that since cast iron is a more brittle metal than stainless steel, it must be made thicker to give it the mechanical strength. So it is simply this – cast-iron saucepans feel heavier because they’re thicker.
I’ve never heard of that before. Only thing I can think of is that the sulfur in the garlic has chelated the iron. Sulfur is a reactive element that binds to many metals, and the iron-sulfur complex is a relatively strong one. That explains the colour (I think), as if the iron ghad been dissolved due to acid it would have been green or red. But don’t worry – the iron hasn’t poisoned you
A cast iron skillet held pasta with basil pesto. I took a bite; it tasted like metal. Upon examination, there was obvious graying on food. An explanation is appreciated and welcome. Cast Iron Skillet, Seasoning Method, Utensils, Food, Combination, Otherwise…
Very interesting. Although I don’t know that to be true, it is certainly believable. Many metals alloy irreversibly, and it is entirely possible that lead alloys with iron under these circumstances
I think it should be known that hundreds of Sauce/Gem/Muffin pans have been contaminated with lead over the years. This is NOT lead left over from casting, just used to melt lead for sinkers, bullets, and even plumbing Etc. Once a piece has been used to melt lead it should be destroyed, as there is no proven way to remove it without melting it to the points you speak of above. Not just pans from China, Vintage American pans have been used for this also. You can buy a lead test kit from Lowe’s in the paint section or order them from Amazon, Red 3M package that gives instant results. I wont buy used iron without testing it first, and over the last few years have came across 5 pieces of American iron that was positive.
Lots of scary claims out there about this… I think I’ll trust Dr.Chemical’s science.
Also, cast iron requires “seasoning” which is a process of oiling and heating which lays down layers of natural non-stick coating, and seals against rusting. Not even sure if food contacts the actual iron surface. (?)
Use of detergent and abrasives is a no-no, with a soak and a wipe sufficing all but the very worst messes, and an properly aged pan is like gold!
Zinc and Cadmium would also boil off using the same logic, but chromium probably wouldn’t. Actually the casting temperature is higher than I said in the article – about 2500 degrees – way above the boiling point of these metals. But of course trace amounts would still remain. I’d imagine you’d get the alloy equivalent of an azeotrope happening to some degree
Well, I guess there is no such thing as impure cast iron then. Lead (we are being lead to believe) will simply boil off. How about the long list of other metals which may be found in scrap yards? Will cadmium, zinc, chromium, etc. all boil off?
I have sold cast iron items from China for 15 years. Much of it looks good but is weak and will break with little force applied due to it’s poor quality. The breaks show irregular grain and discoloring that appears to be contaminants. It does have one big competitive advantage, it’s inexpensive, so it sells.
The stuff I sell isn’t cookware or utensils that come in contact with food, therefore the risk is minimal.
I am aware that this is anecdotal and I can offer no proof of impurities.
So what about the seemingly logical assertion that lead will “boil off”. It isn’t proof either. Molten iron is heavy, will lead really boil off when mixed with very heavy and viscous molten metal? Isn’t that how a pressure cooker works? Water will boil at a much higher temperature when under pressure.
If we are to know the composition of Chinese cast iron cookware, it must be laboratory tested. Do any Chinese companies or US importers of Chinese cookware have lab test results? Has anyone seen a lab report on Chinese cast iron cookware? I would be very interested to see a report but remember that there are many small smelters in China. Which one smelted the iron that was cast to make the Dutch oven you are considering?
No government or industry regulations and many small unregulated manufacturers mean that no one can say with any certainty that a product is pure cast iron, or what impurities it contains. It’s not even possible in a large percentage of Chinese products to determine where they were manufactured and by whom.
I think good sense requires caution, but the low price means that many people are willing to take the chance. So it sells.