Steam and the Heating Sweet Spot
The sweet spot for steaming milk falls between 140°F and 155°F, with smaller drinks on the lower end and larger drinks on the higher end. A quick rule-of-thumb we follow is to steam just until the frothing pitcher becomes a little too hot to hold comfortably.
What is the Best Temperature for Latte Milk?
Using a Thermometer
If you're using a thermometer, you'll want to learn about lag time and how to read a frothing thermometer to correctly gauge the steaming process.
How to Use a Thermometer When Frothing Milk for Latte and Cappuccino