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>What's different between “渋くて苦味“ and "渋い苦味"? The indications of 渋い and 苦い are so similar. It is like 赤くて紅色 and 赤い紅色. And, as Yamato-san says, I personally haven't heard 渋くて苦味, an expression like （形容詞)くて(名詞）. I dare not say it is ungrammatical but say it is so rare(※） ーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーー So let me change your example into 1). "甘くておいしい” and 2)."甘いおいしさ” The grammatical difference between 1). and 2) is 【"甘くておいしい” is an adjective while "甘いおいしさ”　is a noun.】 - "甘くておいしい” = "甘く（形容詞の連用形）＋て＋おいしい（形容詞の終止形） 　　　　　　　→　sweet then delicious →　delicious because it is sweet - "甘いおいしさ”　= "甘い（形容詞の連体形）＋おいしさ（形容詞が名詞化されたもの） 　　　　　　　→　sweet deliciousness →　good taste of sweetness. ※ If it is “渋くて美味”, then that's OK because 美味 can be interpreted as a shorten form of a so-called 形容動詞, "美味だ“. But I haven't yet personally heard the 形容動詞,"苦味だ“，so I believe it is not appropriate to say "渋くて苦味。(period)“

There is no big difference between the two, I suppose.