Definition of 灰汁 (あく)

noun
1.
lye(usually kana)
2.
harsh taste, bitter taste, alkaline taste, astringency(usually kana)
3.
scum (on a soup, broth etc.)(usually kana)
4.
(excessive) self-assertiveness, strong individuality, strong idiosyncrasy(usually kana)(also written incorrectly as 悪)
Other readings:
アク
Notes:
  1. gikun (meaning as reading) or jukujikun (special kanji reading)
Related Kanji
ashes, puckery juice, cremate
soup, juice, broth, sap, gravy, pus
Example sentences(showing 2 results)

When the scum stops appearing pour the syrup back into a clean bottle and keep it in the fridge

4.
すんぜん
寸前
よわ
弱火
いち
もう一度
4. Just before bringing it to the boil, set to a low flame and remove the scum again