So you walk into a caffè in Italy and you drink the finest ristretto you’ve seen in months. So what is it that makes the cofee so perfect? The right answer; is a sequence of events that begins with the green coffee bean, roasting, water filtration, machine and the technique.
Roasting of coffee beans transforms the chemical and physical properties. The roasting process is what produces the characteristic flavor of coffee by causing the green coffee beans to expand and to change in color, taste, smell, and density. But the making of espresso coffee is never as easy as it looks. Many use fully automatic machines at home, as well in professional environments. I use a custom-made machine, fully manual (Strada) constructed in Italy by La Marzocco.
The basket known as a porto-filter needs to filled with the exact amount of ground coffee (from my Mazzer grinder) in order that you get a nice consistency grain fine to coarse.
The timing of the coffee filtering through the porto-filter (under pressure) is part of what makes bitterness. The amount of ground coffee varies, and I use is twenty-three grams into the porto-filter. This makes it to the line inside basket indicating the right fill. The first three seconds I use 3bar pressure for three seconds, and finish up to 11+bar until 23 seconds where I wind it down avoiding too much white cream. The end result is a nice ristretto.