Sourness and acids with

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

(Carbonation)

炭酸(たんさん) 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.

Manga panel from あずまんが大王 showing example of Bad at carbonated drinks with 炭酸.
あずまんが大王 » Volume 2年生 » Page 46

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.

(あゆむ):
「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(たんさん)(けい)なんか()きそうだぞ」
“Yeah, that should be fine, right? Actually, carbonated stuff might work even better.”
(あゆむ):
「あかんあかん炭酸(たんさん)苦手(にがて)やねん」
“No no, I can't do carbonated drinks. I'm bad with them.”
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Taste

(Sourness)

酸味(さんみ) means a sour taste or the degree of sourness in food and drink.

It combines 酸 (sour) with (taste) to show a sour taste.

Manga panel from ご注文はうさぎですか? showing example of That coffee with それ.
ご注文はうさぎですか? » Volume 1 » Page 11

Sampling the second coffee, Cocoa mistakenly identifies the coffee as Kilimanjaro. Chino corrects her.

ココア:
「この酸味(さんみ)…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.”
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