The process of espresso brewing is so demanding that only the best coffees can be put through the process and still delivering a satisfying, balanced beverage. It requires careful attention and, if done properly, it will persuade the highest quality coffee beans to release their colour, texture, flavour, and aroma in a concentrated liquid, and cause an emulsion of coffee oils to rise to the surface. There are six elements that need your close attention in order to successfully brew the perfect espresso.

1. Temperature: Espresso needs to be brewed at a temperature that is below boiling. Optimum temperatures range from 92 ºC to 95 ºC -197 ºF to 203 ºF-.

2. Grind: The grind of the espresso blend or single origin is critical to the success of the drink. The correct grind can only be determined by brewing an espresso and monitoring the extraction. We recommend an extraction of 23 – 27 seconds.

3. Quantity: The quantity of espresso used will also affect the correct particle size, extraction rate and overall flavour of the espresso. We recommend 7 – 8 grams per serving.

4. Tamp: The proper tamp compacts the ground coffee to ensure the water passes through the grounds instead of around them. Tamp pressure will depend on the coffee ground particle size, but should range from 30 to 60 lbs. Place your portafilter on a bathroom scale to obtain a reference. There is great debate on the proper tamper. We encourage you to experiment. We recommend a slightly convex tamper as this dome will increase outward pressure against the coffee filter basket. The sides of the basket allow water to slip past the coffee. Increasing the tamp pressure outward deters the water from successfully slipping past the coffee grounds.

5. The Extraction: If your machine allows for it, wet the coffee, and then supply full pressure (8-9 bars). The espresso should first extract as a thin black stream, then slow to a rich, brown, and frothy liquid stream of espresso. Stop the flow at 0.36 ml – 0.44 ml -1.25 oz to 1.5 oz-.

6. Colour, Texture, and Taste: A properly brewed espresso will have a marbleized appearance and a “crema” or foam that dissipates slowly. The bubbles of the “crema” should be tiny. Any white foam indicates an overextracted espresso, which would have a bitter taste. A good espresso will have a full mouth feel, faint aroma in the cup, and complex tastes that develop and progress as it passes your palate. It should finish on the middle of the palate with notes of coffee, chocolate, nuts, grains, berries, etc. A great espresso has a lasting finish and will maintain its flavour even as it cools.

Source: www.pacificespresso.com