Refrigerate the milk. Cold milk foams better than warm milk, so fill a stainless steel frothing pitcher with 100 milliliters (3.3 ounces) of whole milk (or barista-style almond milk, oat milk, or coconut milk) and refrigerate for about 20 minutes.
Grind the coffee beans. The best espresso comes from freshly ground coffee beans, preferably ground with a burr grinder, which produces more uniform particles than a blade grinder. Baristas will typically grind the beans directly into the portafilter for the freshest coffee possible.
Tamp the grounds. The next step is tamping. A tamper is a small, flat round weight with a handle, kind of like a stamp. You use the tamper to press the coffee grounds into an even disc. Tamping will ensure that the portafilter can go into and come out of the machine properly and maximize the water's contact with the coffee. Don't press too hard, or the disc will become compacted. Apply light pressure, and release with a slight twist.
Prepare the cup. Warm up a 160-milliliter cappuccino cup by pouring boiling water into the cup.
Pull a shot of espresso. Gently slide the filter basket into the machine and turn the handle to lock it into place. Pour the hot water out of the cappuccino cup and place it underneath the portafilter. Depending on the design of your espresso machine, you'll need to flick a switch or press a button, and the coffee will stream out into the cup.
Steam the milk. Your machine will have built-up steam that you can now release using the steam wand. Release a tiny bit of steam into a rag or sponge to clear the wand of any residue. Take the milk out of the fridge and insert the wand into the center of the frothing pitcher. Keeping the wand submerged, froth until the volume of the milk has increased to 125 milliliters and the temperature is about 130 degrees Fahrenheit. Keep the wand near the top of the milk initially and gradually lower it deeper into the milk as the milk increases in volume.
Pour the milk. Slowly pour the milk into the cappuccino cup on top of the espresso, and finish with a foam layer. Serve immediately.