火を通す (ひをとおす) Japanese meaning | KotomoraMeanings
1
expression, godan verb (-su)
cook; heat; apply heat to
Used when heat is applied to food, often to make it safe to eat or to prepare it. Implies cooking through or heating sufficiently, not just warming.
す
と
甘
く
なる
。
This vegetable becomes sweet when you cook it.