The machine is naturally also an important factor in making a coffee or espresso crowned with a delicious crema. However, apart from the machine, other factors are decisive for making a "Schümlikaffee" as it is called in Switzerland:
The crema, the thick, golden-brown foam which is formed on the prepared espresso, is made up of oils, proteins and different types of sugar, and contains a major part of the espresso aroma.
Coffee blend decisive
The more oils a coffee blend contains, the less stable the crema. For this reason espresso coffee blends often contain a certain percentage of Robusta beans, as these beans only contain around 10 percent oil in comparison to the quality, highly-aromatic Arabica beans, which contain around 16 percent.
If the espresso cups are not clean and if they have grease residues on the insides, the crema will also collapse more quickly due to the lowered surface tension.