StepDoWhy
PanHeavy-bottomed, rinsed with cold water firstEven heat; the film keeps milk from catching
HeatMedium-low, never highHigh heat scorches and boils over fast
StirStir and scrape the bottom the whole timeStops proteins and sugars sticking and burning
StopAt steam and edge bubbles (~82°C), not a boilHot enough without scalding or boiling over