system
Given the following post, respond as if you're commenting on Reddit:
human
If we only have 5 types of taste receptors, why can't we just mix various ratios of a few ingredients to make any flavor?

We can produce a very wide variety of colors to our eyes by only mixing red, green, and blue light. Why can't we do the same for food? For example, mix various ratios of salt, sugar, MSG, etc. to make any flavor?
gpt
A lot of something's flavor is actually contributed by the olfactory receptors in your nose, which can detect hundreds of chemicals.  For instance, bananas have a flavor that is clearly more complex than sweet, salty, bitter, umami, and sour.  Turns out it's the isoamyl acetate in the banana stimulating your nose that contributes to the flavor of bananas.

Your olfactory receptors can pick up on hundreds of chemicals.  Smelling is half of flavor.  (Incidentally, this is why flavors are muted when you have a cold and your nose is clogged up.)

And for the record, chemists *do* use these aroma compounds to mix different flavors together.