Espresso

Use clean brewing equipment
Forget the old barista superstition about cleaning your porta-filters. Be sure to clean your brewing equipment throughout the day to maintain consistency and quality of espresso beverages. Pay special attention to the filter in the porta-filters.

The grind
Grind espresso immediately before pulling each shot. The espresso grind is very fine which speeds up the staling process. Ground espresso coffee in an unsealed container will stale in a matter of minutes. Stale grounds will result in poor flavor and weak crema. Check to ensure that your ground espresso has the right consistency. It should be close in texture to powdered sugar. To test the grind, pinch a small amount of grounds and roll between two fingers—it should form a ball as you roll it.

The dose
Using a single size porta filter, dose 7-8 grams of fresh espresso. Using a double size porta-filter, dose 16-17 grams of fresh espresso.

The tamp
Once your espresso has been ground and dosed, use tamp to compact the dose in the porta-filter using a force of 40 p.si. It is difficult to gauge pressure without a scale, so as a rough guide, the coffee should be flat and smooth, but not compacted. If the coffee is tamped too hard, the machine will struggle and it will take a long time for the coffee to begin pouring and it will pour in a drip rather than forming a thin stream. Place your tamp on the espresso and lightly twist it to polish the espresso. This will help the pressurized water to flow evenly through the grounds. Your packed espresso will have clean, smooth finish with no pits. Once you have achieved the perfect pack, insert the porta-filter into the group head.

Timing
It but should take between 18 and 23 seconds for a perfect shot of espresso (long, about 40 ml or 1.35 fl oz). A short espresso is typically about half the volume of a long espresso. Timing will depend on water mineral content and pressure, the dose, the grind, the packing force, the model and condition of your equipment, and the water pressure. Faster extractions produce thinner espresso and high acidity. Long extractions are characterized by thick, tiger-striped crema.

Crema
Crema is a golden foam made up of oil and colloids that floats atop the surface of a perfectly brewed espresso. While crema is the most visible sign of a proper brewing, a thicker crema doesn’t necessarily equal a “better” espresso.