Why would different types of pots/pans (made from different metal) give a different taste to food?
Some metal react differently with some food, mostly with acidic ingredients like tomatoes.

Stainless steel and ceramic are non-reactive and should not impart different flavor to the food.

Aluminium, "regular" steel, iron(cast-iron), copper are known to be reactive and will react to ingredients and will change some of the flavors.

I mostly used stainless steel pans and pots (and stainless-steel lined aluminium pans) and don't have issues with "flavoring".

(from http://www.thekitchn.com/food-science-explaining-reacti-73723 )