For me it is the fact that our blood contains iron. I earlier used to believe the word stood for some ‘organic element’ since I couldn’t accept we had metal flowing through our supposed carbon-based bodies, till I realized that is where the taste and smell of blood comes from.
We do have metal in our veins. Blood has metallic taste precisely because of iron, which carries oxygen through our body.
Metal has no taste tho. What yr tasting is you. VSauce or Nilered did a video about it.
You can test it yourself, just degrease and wash a coin. Once clean, no taste.
Years upon years of being told this cannot make me not taste metal from stainless steel cups/canteens and forks, even brand new and/or freshly scrubbed to hell and back. I can’t use stainless steel tumblers because of this - even if I keep my tongue well away from it, and it’s the cleanest dish in the world, it makes the drink taste metallic. No amount of youtubers just insisting I don’t/can’t taste a thing can actually compete with a lifetime of experiencing this problem. And I have, multiple times, tried all the things they say to do to fix the “real” problem - but no. Steel tastes like steel, always.
Hypothesis: this is one of those things some people can taste and others can’t, like how there’s a whole group of “cilantro tastes like soap” people and everyone else is like ???
Of course it is not free metal. Probably oxide. And no, I am not going to taste rust.