Mastering the art of espresso extraction can be an immensely rewarding and enjoyable process. Though the finer details might vary between espresso machines, grinders and coffee beans, the method below is widely transferable. Follow closely and you'll be well on your way to matching any professional barista!
Start with a CLEAN MACHINE
Make sure your espresso machine and grinder are both free of coffee residue and in good working order. Turn them both on and wait for the espresso machine to heat up. Use a high quality grinder with sharp burrs, and grind only as much coffee as you need for each use. For best results, use fresh espresso beans.
Use a FIRM, EVEN TAMP
The amount of coffee (dose), the grind setting and the tamp determine the rate at which the water flows through the coffee. Too small a dose makes it too easy for the water to flow through, which means much of the bean's great flavour will be left behind. Too large a dose makes it difficult for the water to evenly penetrate the puck and extract the coffee's best components. Professionals call this "channeling".
Fill the basket of your portafilter with freshly ground coffee to within 3mm of the rim. Grip the tamper with your dominant hand and press down on the coffee with a firm, even pressure. Carefully remove the tamper, brush away any loose grounds, then tamp once more to polish the puck.
Aim for a 25- TO 30-SECOND SHOT
Fit the coffee-filled portafilter into the machine and start the extraction process. The time of the extraction (the pour) should be no more than 25to 30 seconds.
While brewing, the flow of espresso will have the viscosity of thick, warm honey about the width of spaghetti strands. You should see three main colours: a deep chocolate brown, a bronze caramel, and a golden blond at the finish.
Finish with roughly1 TO 1¼ OZ PER SHOT
After 25-30 seconds, you should have 1 to 1¼ ounces for a single (or 2 to 2½ ounces for a double) shot of espresso. There should be a creamy ¼-inch layer of red-gold crema on the top of the shot, with a chocolate-coloured body beneath. Colours may vary slightly, depending on the type and freshness of the bean.