Sourness and acids with 酸
酸 has the core meaning sour. In scientific compounds, it refers to acid and appears in terms involving oxygen and oxidation.
Etymology
This kanji is a phono-semantic compound comprised of 酉, associated with fermentation and liquor, and 夋 as the phonetic component. Fermentation produces sharp, tangy flavors.
Acids
炭酸 (Carbonation)
炭酸 means carbonic acid or carbonation. In everyday use, it often refers to carbonated water or a carbonated drink.
It combines 炭 (carbon) with 酸 (acid) to show carbonic acid or carbonation.

A case of the hiccups sends Ayumu down the path of trying each of her friends’ potential solutions. Tomo suggests drinking water as a cure.
- 歩
( : - 「ジュースでもええんか?」
- “Is juice okay too?”
- とも:
- 「いいんじゃねーの?あ炭酸
( 系( なんか効( きそうだぞ」- “Yeah, that should be fine, right? Actually, carbonated stuff might work even better.”
- 歩
( : - 「あかんあかん炭酸
( は苦手( やねん」- “No no, I can't do carbonated drinks. I'm bad with them.”
Taste
酸味 (Sourness)
酸味
It combines 酸 (sour) with 味 (taste) to show a sour taste.

Sampling the second coffee, Cocoa mistakenly identifies the coffee as Kilimanjaro. Chino corrects her.
- ココア:
- 「この酸味
( …キリマンジャロだね」- “This acidity… it's definitely Kilimanjaro.”
- チノ:
- 「それがブルーマウンテンです」
- “That is Blue Mountain.”