bitterness vs taste sensation

bitterness and taste sensation both are nouns.

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

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

bitterness: the taste experience when quinine or coffee 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 bitterness include gustatory perception, gustatory sensation, taste, taste perception.

bitterness (noun)	taste sensation (noun)
the property of having a harsh unpleasant taste	the sensation that results when taste buds in the tongue and throat convey information about the chemical composition of a soluble stimulus
a rough and bitter manner
the taste experience when quinine or coffee is taken into the mouth
a feeling of deep and bitter anger and ill-will