Korean fried chicken usually fails before the sauce even touches it. The chicken can be seasoned. The oil can be hot. The yangnyeom sauce can be glossy and ready. But if the coating is too thick, the crust turns heavy. If the batter is too wet, it fries bready instead of crackly. If the powder is wrong for the job, the sauce lands on a soft shell and the whole batch tastes tired after five minutes.