Steaming milk is mostly about temperature. Heat it to the sweet spot and it tastes naturally sweet and silky; push too far and it scalds.
| Stage | Temperature | Result |
|---|---|---|
| Ideal serving | 140 to 150F | Sweet, smooth, silky |
| Upper limit | 155 to 160F | Hot but still drinkable |
| Scalded | Over 170F | Burnt, thin, loses sweetness |
Why temperature matters
Heating milk converts some of its lactose into a sweeter taste, but only up to a point. Past about 160F the proteins break down, the milk tastes cooked, and the foam collapses. Aim to introduce air early for microfoam, then heat to temperature.
Stop around 150F. If you do not have a thermometer, stop when the pitcher is too hot to hold comfortably for more than a second or two. That is roughly 150F.
FAQ
What happens if I steam milk too hot? Milk steamed above roughly 160 to 170F starts to scald, breaking down proteins and sugars in a way that dulls sweetness and can create an unpleasant taste, along with unstable foam that collapses quickly.
See the Espresso Drink Ratios Chart and the How to Make Espresso.