The perceived effect of smelling coffee before drinking it is a placebo effect.

“My favorite way to tell this story is like you know how you wake up and you smell the coffee and then even that kind of perks you up a little bit? They say yeah. And I say did you know that there's a term for that? And they're like oh there is. And I say, "Yes, it's called placebo." Then and then so they laugh and like, "What do you mean?" I'm like, "Coffee doesn't work all factory. It doesn't work through the nose." If you smell it and you start perking up, it's because you're predicting what its effects are going to be before you even ingested it.”