Heat milk. Simmer milk on the stovetop or microwave it. Make sure milk doesn't come to a boil. The ideal milk temperature to froth is 160°F. Don't let milk simmer on the stovetop for long. As soon as you see bubbles forming along the sides of the pan, you can take it off the heat.
Pour heated milk into a French press.
Place lid on the French press and move the plunger up and down, making sure to hold down the lid.Move the plunger until the milk doubles in volume.
Pour frothed milk into a cup of espresso or coffee.
To heat milk in the microwave: Put milk into a glass container and microwave 15 seconds at a time. Heat for 15 seconds, stir, then microwave for 15 more seconds until you see steam coming out of the milk.
Don't overfill. Don't fill more than half the French press with milk since you want to have room for the milk to double in volume. It's best when you fill it up a third of the French press so that milk doesn't spill out.
Don't underfill. The milk must go past the strainer by at least half an inch once the lid is placed. The milk won't froth properly if the strainer is only touching the top of the milk in the French press.
The best froth is when there aren't a lot of big bubbles, just tiny ones that create microfoam. A steam wand from an espresso machine creates the best froth since you have the most control in terms of microfoam and foam. An electric milk frother is next best since it heats and froths milk at the same time. After those two, nothing beats the froth created in a French press for home use.
Make frothy hot chocolate in a French press! Make hot chocolate and pour into a French press. Pump until it doubles in volume and pour into a cup.
When you heat milk, it increases its perceived sweetness so warm milk will taste sweeter than cold. If you're trying to reduce sugar intake, look to heating and frothing milk for your coffee so you don't have to add any sweeteners.