clean & dry basket:
It is ideal to have your portafilter the same temperature as the group head. Make sure to thoroughly wipe the basket free of coffee grounds and residue before adding coffee to the basket. You don’t want any oils leftover from the last extraction.
This is a very important step because it will make or break the shot you pull. It’s best to start your dosage at 18g for a double shot like were demonstrating here and 8g for a single. Using a scale is the most accurate way to monitor your dose and it’s very easy to buy a small digital scale that will fit between the portafilter and drip tray.
level the coffee:
It’s important to level the coffee grounds in the portafilter. Using a ruler or flat object (finger) will help to create a flat surface with more density needed for tamping. An unleveled coffee bed will cause the water from the grouphead to run unevenly through the coffee.
If you do not follow these simple steps, it will result in a shot of espresso with more tart, dry, bitter and harsh notes of flavor with little or no sweetness.
When tamping it’s very important to put an even amount of pressure on the surface of the coffee bed in the portafilter. The main focus here is creating a level coffee puck and not an uneven one.
When this happens, all the water will go to that side resulting in an uneven extraction. Creating too much pressure can result in an uneven puck as well.
Purge (flush) your grouphead. Wait about 3 seconds for the water to come out and this will flush out any oils or residue left over from the last extraction.
Try to insert the portafilter ASAP. By doing this, it will help keep the temperature of the grouphead at a more ideal temperature to pull a better extracted shot.
When pulling the shot keep an eye on the colors. The first color you should see will be a very dark brown. Next you should see a thicker and lighter brown. Eventually the stream will get very light colored, almost a blond. Typically that’s the time you stop the shot.
taste and adjust:
Does it taste bitter? Sour? If so, adjust the grind, temperature or beverage weight and go from there.