Okay, I know somehow or other it became 'the thing' to refer to the smell of blood as 'coppery'. Blood doesn't smell like copper, people. Copper doesn't smell like anything. Metal* doesn't smell like anything.
Blood does taste metallic. (Yeah, I know this because I was the kid who put pennies in my mouth. Cut me some slack, though. I didn't know how disgusting they are. Also, I've had blood in my mouth and the tastes are comparable.) But only to a certain extent.
Yes, we writers have to describe things the best we can so readers can understand what we're trying to convey. Right now, readers have been trained to expect that blood smells coppery. It's a thing.
But seriously, it's a wrong thing. As a reader it trips me up every single time - even when a writer I love love love has written it. And I even get that what they really mean is that blood smells like metal tastes - but saying it that way is weird.
But it's still wrong.
Blood has a tangy smell. It smells sharp and salty (like the ocean - not like table salt, because that doesn't have a smell either). It smells like a butcher shop or a package of fresh ground beef (because of... ya know... the blood). Old blood might smell sour or rancid.
My point is that blood has a lot of smells, but none of them are the smell of metal. Don't believe me? Pick up a copper pan and sniff it. What's it smell like? I can guarantee it doesn't smell like blood. (Yeah, I know what lots of blood smells like. I may not remember much about my accident, but that stays with you on a sensory level.)
Your turn. What's a minor pet peeve you have as a reader?
*It's entirely possible that at some point I have referred to the smell of blood as 'metallic' - because it's a thing, not because it's right. If I have, I was lazy. Forgive me.