The espresso is the starting point for all espresso coffee - approx. 25 ml of espresso extracted in 25-30 seconds. A well-made espresso is characterised by a dark, golden crema. A further sign of a good espresso is that the surface tension of the crema should maintain one teaspoon of white sugar on its surface for 3-4 seconds before falling through.
A Ristretto, meaning "restricted’"in Italian, is normally only the first 15mls of extraction – it is therefore "restricted: in the amount of coffee extracted and captures the sweetest, most intense characters of the coffee. The term ‘Double Ristretto’ is capturing 30 ml of espresso, made up from 2x 15 ml shots.