Drinking completely with 〜終わる

Grammar Explanation: Completing an action with 〜終わる

Chino explains the steps to perform coffee fortune telling.

チノ:: 「飲(の)み終(お)わった後(あと)に残(のこ)ったコーヒーの模様(もよう)で占(うらな)うんです」; “After you've finished drinking it, we tell fortunes from the patterns left in the coffee.”
Step:: 「① 飲(の)みおわる」; “① Finish drinking”

In Chino’s dialogue, 終(お)わる is used because finishing a drink is the normal completion of the action of drinking.

See Also