Grind, Measure and Tamp
Grind coffee immediately before brewing; a burr grinder produces the best and most consistent espresso grind. Pay careful attention to the consistency. If the grind is too coarse, the coffee will be thin and weak — if the grind is too fine, the coffee will be over-extracted and bitter.
Measure coffee to fill the filter basket inside the portafilter. Press down on the grounds firmly with a tamper so they are flat and even.
Insert the portafilter into the machine, and place a demitasse under the spout. Activate the pump by pulling the handle or pressing the brew switch.
An espresso should take 20-25 seconds to brew in a home espresso machine with a strong pump, and should have the consistency of flowing honey. As the espresso flows into the cup, there should be a caramel-colored foam ("crema") on top. When the espresso flow begins to develop ripples, turn off the switch or pull the cup away—the remaining fluid tastes weak and bitter. A fully extracted, properly prepared espresso yields 1 to 1-1/2 fluid ounces (30-45cc), about the size of a shot glass or about a half a small demitasse cup.
A properly-made espresso is complex and balanced, with a concentrated yet sweet flavor. If you prefer it weaker, add hot water or hot milk to the brewed espresso. Drink immediately to savor the complexity and ephemeral flavor.