STEP 2. STEP 1. Building a flat white is pretty straightforward: you just need to make a standard double espresso shot, steam up some milk to about 60 Celsius (about 145F), and have a spoon to hold back any thick foam while pouring. • For making a single flat white, we use a little under 3 ounces ( or 100ml) of cold … You need one double shot of espresso for one flat white, which typically takes about 15 grams of coffee and 60 milliliters of water. Make around 35ml espresso using your coffee machine and pour into the base of your cup. Steam the milk to 55–62 °C. Hold the jug so that the spout is about 3-4cm above the cup and pour the milk in steadily. While the shots are being poured by your tool of choice, get to steaming the milk. At-home milk steaming is a bit more complicated than at-home espresso making. Method. How to make a perfect flat white Pull a double espresso into a cup or glass. Steam the milk with the steamer attachment so that it has around 1-2cm of foam on top.