Preheat your cups; it makes a big difference. By the time you hit the bottom of your cup, or finished making the coffee for the last person, the first shot can be very cold. Boiling water usually makes the cups too hot to hold, but filling them with hot water from the tap works well. If you put hot tap water in your cups before starting to brew coffee they will be ready by the time you get everything ready. You will also want to warm the brew head before starting. If you do not do this the heat of the water will be dissipated by warming the brew head. If you are making multiple cups leaving the brew head in the machine between cups should keep it warm.
– Make sure the coffee is ground for an espresso machine. If the coffee is too coarse the water will go through too fast and will not extract the nectar from the coffee. If the coffee is ground too fine the water will not be able to travel through the grounds properly and may lead to over extraction. Think of salt as a general rule. The best, of course, is to grind your own, but you can tell your coffee supplier to grind for an espresso machine. Until you get the knack of exactly how fine is fine enough you might want to buy pre-ground coffee to get an idea of what is correct. Espresso is definitely one place that a whirly blade grinder will not work.
– Make sure the filter basket is full, and tamped correctly. This is another one of those places that a little experimentation is in order. If the coffee is tamped too hard water will not flow through. If it is not tamped hard enough the water will run through the grounds too quickly. Every machine is a little different. Experimentation is the key. So be sure that the coffee is level. If it is not you will be providing a path of least resistance for the water to go through.
– Turn off the machine or move the cup away as soon as you see the streams of coffee coming out of the machine have become thin. If you keep going after this point, you’re just pumping bitter over extracted garbage into your cup. The more you run out, the worse it will taste. If you want a longer drink, make a double, or add hot water to your espresso to produce an Americano.
– Espresso should be served immediately. Ideally, the crema on an espresso should be all one color and preferably a very light honey color. If the crema has dark streaks, then the beans you have may have been burnt too much in the roasting process. Alternatively, the temperature on the machine itself could be set too high, and the coffee’s being burnt by the water. If there’s uneven crema, then either the coffee has been left sitting too long after being ground, or the dose in the handle hasn’t been tamped down firmly enough.