Start with a matcha base
Sift 2 grams of a latte or premium grade matcha into a small bowl and whisk with 40 to 50 milliliters of water at 70 to 75 degrees Celsius until smooth. Whisking matcha directly into milk tends to leave clumps because milk proteins coat the powder before it hydrates.
Adding the milk
Steam or warm 150 to 200 milliliters of milk to about 60 to 65 degrees Celsius and pour it over the matcha base. For iced lattes, fill the glass with ice, pour cold milk, and add the matcha base last so the layers stay visible until you stir.
Choosing milk
Whole dairy milk gives the roundest body. Oat milk is the most popular plant option because its starches and fats carry matcha's flavor without curdling. Lighter milks such as almond or rice can taste thin under matcha, and very acidic plant milks may separate when heated.