We all like the smell of vanilla. Because the smell can gives us euphoric felling.But when we taste it, taste bitter, how it can happen , when our taste senses and smell senses are intertwined.
Vanilla doesn’t smell sweet. It smells like vanilla. Your brain associates vanilla with sweetness, so you think it smells sweet.
The brain can do weird things like that. Like how you aren’t really capable of feeling wet. You use a bunch of other cues to determine if your hand is wet or dry, and it’s why its so hard to tell if laundry is dry after it’s become cold.
This link on the wetness thing for the curious.
Certain things are not in fact sweet, but are highly associated with “sweet” in our culture – and thus when we smell them, we smell “sweet.”
Vanilla, cocoa, cinnamon are great examples: not one of these is sweet. Put them on your tongue and they’re all bitter. Put them under your nose: do you smell sugar?
But a huge swath of western cooking only uses these things in sweets, and so we’ve drawn that association. Start using them in other dishes for a while, and you’ll notice they no longer smell “sweet” to you.
Sweet is mediated predominantly by hT1R2 and hT1R3 g-protein coupled receptors on the tongue, largely found on the tastebuds of fungiform, vallate, and folliate papillae. These receptors are not found in the nose, and odorant receptors for glucose have not, to my knowledge, been identified. In fact, in animal model experiments, glucose vs. other sugar oligomers have been used as rewards/punishments coupled to smell stimuli – because glucose and the other carbs did not themselves influence the experiment through smell
It isn’t actually sweet. You just think it is because it’s always used with something sweet, so when you smell it you go “oh, it’s sweet”. Very dark chocolate (or just cocoa powder) is a good example, because that doesn’t smell sweet or taste sweet, but you think chocolate is sweet because usually it’s put in something with lots of sugar
Source: lots of cooking .
Smell and taste are not intertwined, smell and flavor are. You can’t really smell something as salty, sour, bitter or sweet. Those are tastes, and your tongue is responsible for detecting those.
The way these molecules interact with your olfactory nerves and your taste buds is different, and they are interpreted differently. With time you may learn to correlate certain smell/flavors with tastes, but these are merely based on experience.
Try sniffing around a bunch of salt, for instance. Or try smelling strong chocolate or coffee with and without sugar if you can, without knowing which is which. (They have to be similar brand/type). Before you touch it with your tongue you won’t really know if it’s sweet.