Vapor
Noun
ゆげ
ビエトのおでこから出ている湯気、なんだかいいにおいがするんだよね。
The vapors coming out of Viet's forehead smell nice for some reason.
それ、まだ湯気が立つほどあついから、気を付けてね。
That's still steaming hot, so be careful.
美味しい寿司飯を作るには、しゃもじを使って、湯気が立つ炊きたての熱いごはんに酢を混ぜる必要があります。信じられないかもしれませんが、実際に米一粒一粒を潰さずに酢を混ぜるには技術が必要です。
To make good sushi rice, you need to mix vinegar into steaming hot, freshly cooked rice, using a paddle. Believe it or not, it actually takes skill to mix the vinegar into the rice without crushing the individual grains.
Hot water's energy isn't the hot water itself, it's what comes out of it (when it's boiling, for example). This is the steam and vapor.
The ゆ part of the reading makes sense. The げ part for 気 is a bit of an exception. Just think of yourself standing in the steams and vapors. You're getting all hot and sweaty, but the feeling makes you incredibly happy and gay (げ). Then someone asks, as they look at you in the steam: "Hey, you gay?" (ゆげ). You answer however you want to answer.