How much do you want to bet that not one of these people has had any work done to figure out if they actually have an iron deficiency?

^You're not wrong. They also likely self-diagnosed with 'wheat belly' or one of the other middle-class granola favourites.

My first thought.

Yup! http://goaskalice.columbia.edu/answered-questions/does-cooking-cas t-iron-pots-and-pans-add-iron-our-food

This is why so much stir fry tastes sour and metallic. Once I started using stainless steel I haven't turned back. Doesn't the taste bother you?

I typically do not stir fry in cast iron, so I can't speak to that. I'll usually use it for frying meats or veggies (potatoes, tomatoes, green beans, mushrooms, etc) that I think finish off in the oven. Never tastes metallic. I'm not sure how to account for your experience. Maybe either: cooking method brings out the flavor you taste; you're particularly sensitive to a taste that I am not; your cast iron was of a poor quality (not fully iron etc) that contributed to the taste.

*that I then finish off in the oven...

Oscar that sounds very much like the off-flavour food gets from an improperly seasoned (usual high carbon steel) surface.

Get it washed in hot soapy water the first time (disregard anyone who give the myth about not washing it ever, this is how basically every chinese mom does it) then dry it completely, add wok oil with a high smoke point and cook the shit out of several batches of chinese chives which will absorb that metallic tang.

Build up a patina by cooking in it regularly, and just wiping it clean (no more soap after the first time).

Oh and make your wok hot as fuck before you add oil to it, the amount of cooks I've seen failing that most basic step before frying is too damn high.

Well there is iron, and then there is iron, Simon. Cast iron is typically plain iron with a great excess of carbon, like >2%, some silicon to lower the melting point, and the classic magnetite coating. Mostly I use the cast pans for roasting nuts and breadcrumbs, but as you say, they don't corrode as easily and disflavor the food ( mainly because of the finish )

I used to stir fry in woks, which are typically rolled steel with (relatively) lower carbon content and no special finish. That is the cookware that puts the most iron into your food, especially if you try to make a sauce by delaminating the pan with water or wine.

Now I use stainless steel and both sticking and corrosion are a thing of the past. God bless austenitic steels!

@Bags. Yes, by dint of great effort, you can over the course of years achieve a primitive carbonitriding of the surface with enough grease and burnt offerings. Why do they not actually nitride or blue the cookware? Too lazy, I suppose. All of that nonsense is obviated by austenitic steels. 314L stainless can't be beat.

Thanks for the informed response, Oscar. And would you look at that, austenitic sometimes contains molybdenum! And I thought molybdenum was only used for philosophical thought experiments.

Clad stainless is good for home cooks who want low upkeep, I'll give you that but heat transfer sucks on the low to mid end of the pricerange and it makes for eternally horrible fried rice.

If you tell me your fried rice never sticks to stainless, you're either a liar or a man who uses waaay too much oil :)

I laughed, but you have to take in a pretty serious dose of iron to start vomiting blood.