Every barista will have his or her espresso making method. Here is ours.
It all starts with water. No coffee grounds, no matter the quality, can overcome an association with poor water. It must be fresh and very hot. Yes, even water can get stale, thanks to mildew, poor cleaning practices, and inadequate filtering. The optimum temperature is 203F (95C), nearly boiling.
Next comes the coffee. Select arabica - whether from Brazil, Bogota, or elsewhere, grown above 3000 feet (915 m) and delivered fresh for roasting. Either self-roasted or bought within a few days after, the coffee should have that 'fresh food' smell. Robusta - though easier to grow and more disease resistant - has more caffeine and less flavor. It should be reserved for those quick pick-me-up cups, not used for an espresso to be savored.
Finely ground in burr, not blade, grinders the roast should be dark - French or Viennese. The name refers to the color, not the origin. Blade 'grinders' actually chop, not grind. Burr grinders have pyramid shaped teeth on two plates that grind the beans between them.
The distance between the plates determines the fineness of the granules. Sand grain-sized is good, powder is too fine, and small-gravel too large. Of course, the grind should not be exposed to air any longer than necessary. Coffee, like any food, will oxidize and absorb odors from the air. Neither is conducive to a good cup.
And, last but not least, a good espresso requires a clean machine of good quality. 'Good quality means: generates heat by boiler or thermoblock and is capable of producing pump pressure of 9 bar or better. A 'thermoblock' heats water as it passes through the machine on the way to the pump. Avoid the cheaper units that rely on steam to create pressure.
Now you have the basic elements. Next comes the process.
Pre-warm the equipment by running good water through a clean machine. You can turn the machine on, let the water heat, and run a cup through with no coffee to warm the surfaces and flush the system.
Add your ground roast and pack down slightly, as you would pipe tobacco. Just as with pipes, you should be feel some springiness, but the coffee shouldn't scatter.
Insert the hopper in the machine firmly and place a warmed espresso cup at the outlet. Start the machine and in about five seconds you should have a thin, steady stream. (About 20 seconds for a double shot.)
For a cappuccino, warm half a cup of organic milk in the microwave about 90 seconds, froth, and add to the espresso. Garnish to taste with cinnamon, nutmeg or chocolate. For those who like it sweet a little organic sugar goes a long way.
Simple, straight forward, and easy. Start with good ingredients, keep your equipment clean, and don't burn the roast. The result? A great cup!