Once in the cup, coffee can be visually analyzed based on look and color.
Texture, firmness, the foam persistence all show whether coffee was correctly extracted, while color and the characteristic of the head or foam can reveal more about the type of blend: 100% arabica, arabica and robusta or 100% robusta.
A correct extraction results in a fine texture foam, a hazelnut color, a 4-5 mm thickness and a good persistence.