Tips for Making Perfect Espresso

Espresso is made by forcing hot water (not boiling water) under pressure through a "puck" of finely ground coffee. The finer the grind, the denser the puck, hence the more pressure required to force the water through it. The most important rule of making perfect espresso is that the pressure used should push the water through the coffee puck in 25-30 seconds. If it takes longer than this, the espresso will be bitter.

Therefore the grind needs to be tailored to the pressure of the espresso machine. A single shot contains 1.5 ounces of liquid that is pushed through a tablespoon of coffee grounds in 25-30 seconds. A double shot contains 3 ounces of liquid pushed through 2 tablespoons of coffee grounds in the same amount of time (25-30 seconds). Lever espresso machines have pistons in which additional pressure can be applied by external force (by you) to adapt the time as needed. With a lever espresso machine, you can compensate for an incorrect grind with your own strength.

To make the perfect espresso you need to have the proper espresso machine, a good coffee grinder, and excellent coffee. Minimally, you need a pump-driven machine delivering at least 9 bars of pressure. (Note: 1 bar = 1 Megadyne per square centimeter = 0.987 atmospheres.) The espresso machine should have a boiler, and two sizes of portafilters (one for single, and another for double shots). Ideally, the coffee used for making espresso should be freshly roasted. For best results, try to use 100% Arabica beans. Robusta is strong, but is usually of poorer quality, having a harsher flavor. While Robusta can be used to add character to a blended coffee, the amount of Robusta used in a blend to be used for espresso should be small.

To make espresso, it is good to preheat the portafilter by running hot water through it. You should also start with a pre-warmed espresso cup. Cups can be warmed on the heating tray of your espresso machine (if your espresso machine has one), or you can pour some hot water into the cup, and then drain it. The simplest way to preheat the portafilter is to run the espresso cycle on your espresso machine without any coffee in the portafilter. In fact, you can run it into your cup to heat that as well.

Then, grind the coffee, and scoop 2 tablespoons of coffee into the double-shot portafilter. Most of the espresso machines come with a pre-measured scoop (for a single shot) so two scoops of freshly ground coffee are easy to measure. Tamp the coffee in the portafilter with the tamping tool, using an even motion. The tamped coffee should be level and compacted. Brush off any loose grounds.

Lock the portafiler into the espresso machine and place the preheated espresso cup under the nozzle. Start the pump. Stop pumping after 3 ounces of espresso are produced. The coffee will be darker at the beginning of the extraction, and will change to a golden cream color (the "crema") by the end. Uniform pressure should be used throughout the process, which should be adapted so that the process take 25-30 seconds; no more and no less.

Tips for brewing the perfect espresso:

• The portafilter should be clean.
• Always preheat the equipment (machine, cup and portafilter).
• Soften the water you are using to make the espresso or use bottled distilled water.
• Use a fresh espresso blend and grind the coffee beans only before making the espresso.
• Check the grind and change it if you don't like the espresso it produced.
• The extraction time should be 25-30 seconds. Adjust the grind if it is not.
• Use 1 Tablespoon of coffee for a single shot, and 2 Tablespoons for a double shot.
• Tamp the coffee grind evenly into the portafilter.
• Wipe the loose coffee grinds off the portafilter before locking it into the brew head.
• Press the correct button for the size you want (single or double shot).

...written by your friends at The Coffee Brewers