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lye
harsh taste; bitter taste; alkaline taste; astringency
scum (on a soup, broth etc.)
(excessive) self-assertiveness; strong individuality; strong idiosyncrasy
野菜のあくを取ってください。
Please remove the harshness from the vegetables.
あくが強い食材は下処理が必要。
Bitter ingredients need prep work.
あく抜きをしないと苦い。
It's bitter without removing the bitterness.