Around 60 to 65 °C. That is hot enough to be a hot drink and below the point where milk starts to taste of itself in a bad way.
Why the ceiling matters
Milk contains lactose, and heat breaks it down. Below about 65 °C the milk tastes sweeter as it warms, because heat makes the existing sweetness more perceptible. Past roughly 70 °C the proteins denature and the lactose starts to scorch, and the flavour turns flat, cooked and faintly eggy.
Once that has happened it cannot be undone. Overheated milk is overheated.
How to judge it without a thermometer
Put your hand on the side of the jug throughout. Stop when it becomes uncomfortable to hold — around three seconds before you would have to let go. That lands most people between 60 and 65 °C, and it works because human skin is a surprisingly consistent sensor in that range.
Almost every professional does it this way. A clip-on thermometer is a good idea for the first fortnight, until your hand learns the number.
Why serving temperature disappoints people
A drink at 60 to 65 °C is noticeably cooler than tea or drip coffee, and people used to those often think a flat white is lukewarm. It is not — it is at the temperature that keeps the milk tasting sweet. Warming the cup helps considerably, because a cold ceramic cup takes several degrees out of the drink immediately.
Plant milks want less
Oat and soy have a narrower window and collapse sooner. Stop a few degrees earlier than you would with dairy — around 55 to 60 °C.
Questions people actually ask
Can I reheat milk that has gone cold?
You can heat it and it will not foam properly again. Re-steaming already-steamed milk gives thin, bubbly foam and a cooked flavour. Steam what you need and pour it.
Why does café milk taste sweeter than mine?
Usually temperature. Home users overheat, and heat is what destroys the sweetness. Stopping five degrees earlier is often the whole difference.
Last reviewed 8 August 2026