Ristretto
General
Ristretto means "shortened" and is one of the more difficult versions of an espresso.
There is a great deal of discussion about the definition of the "true" Ristretto, from the various possibilities we present those of which we are not only convinced in terms of taste, but which also represent in the eyes of most barista's the correct preparation of a Ristretto.
Preparation of a ristretto
Basically, a Ristretto is a shortened espresso.
This means that the same extraction time of an espresso (25 seconds) gives less liquid (about 15-20ml).
There are two ways to achieve this:
1. | More Coffee - Same Grindness
The grind of your mill remains the same, but more coffee beans used. Some sources recommend a 1:1 ratio-i.e. 1g of ground coffee on 1ml extraction.
This would be about 15-20g of ground coffee for a ristretto. The advantage of this method is, that the often tedious process of finding the right grind setting does not have to be started anew every time.
2. | Finer grind-same amount of ground coffee
The amount of ground coffee remain the same (approx. 7.5 - 9g espresso), however, the degree of grindness is finer so that the extraction time results in 25s for 15-20ml of coffee.
The result is intense taste with emphasis on bitter notes.
What is NO Ristretto
Ristretto does NOT mean that I finish the extraction of my espresso earlier (ie at 15-20ml extraction).
Why?
Stopping the extraction sooner would mean that I only emphasize the first two thirds and thus get a bitter coffee and perhaps even lose desired flavors.
Ristretto does NOT mean that the espresso is over-extracted, ie the degree of grinding or the amount of coffee is too high. Over-extraction is easily noticeable: if the coffee does not flow uniformly into the cup, but "dribbles".