sourness vs gustatory sensation

sourness and gustatory sensation both are nouns.

Word	Noun	Adjective	Verb	Adverb
sourness	Yes	No	No	No
gustatory sensation	Yes	No	No	No

As nouns, gustatory sensation is a hypernym of sourness; that is, gustatory sensation is a word with a broader meaning than sourness:

sourness: the taste experience when vinegar or lemon juice is taken into the mouth
gustatory sensation: the sensation that results when taste buds in the tongue and throat convey information about the chemical composition of a soluble stimulus

Other hypernyms of sourness include gustatory perception, taste, taste perception, taste sensation.

sourness (noun)	gustatory sensation (noun)
the property of being acidic	the sensation that results when taste buds in the tongue and throat convey information about the chemical composition of a soluble stimulus
a sullen moody resentful disposition
the taste experience when vinegar or lemon juice is taken into the mouth