잔에

in the glass

→ 잔
phrase Rare #16,544
in the glass 잔 means a drinking glass or cup, and 에 marks the location. In phrases like 두 잔에, 잔 is a counter meaning “glasses of.”
KO: 잔에 물을 따라 주세요.
EN: Please pour water into the glass.

세상에나, 잔에 구멍이 났나

Good grief, does this glass have a hole in it?

— 머시니스트 (2004)