sourness vs taste sensation

sourness and taste sensation both are nouns.

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

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

sourness: the taste experience when vinegar or lemon juice is taken into the mouth
taste 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, gustatory sensation, taste, taste perception.

sourness (noun)	taste 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