The length of the shot can be ristretto (or stretto) (reduced), normale/standard (normal), or lungo (long): these may correspond to a smaller or larger drink with the same amount of ground coffee and same level of extraction or to different length of extraction. Proportions vary and the volume (and low density) of crema make volume-based comparisons difficult (precise measurement uses the mass of the drink). Typically ristretto is half the volume of normale, and lungo is double to triple the normale volume. For a double shot, (14 grams of dry coffee), a normale uses about 60 ml of water. A double ristretto, a common form associated with artisanal espresso, uses half the amount of water, about 30 ml.
Ristretto, normale, and lungo may not simply be the same shot, stopped at different times[ – which may result in an underextracted shot (if run too short a time) or an overextracted shot (if run too long a time). Rather, the grind is adjusted (finer for ristretto, coarser for lungo) so the target volume is achieved by the time extraction finishes.
A significantly longer shot is the caffè crema, which is longer than a lungo, ranging in size from 120–240 ml (4–8 US fl oz), and brewed in the same way, with a coarser grind.
The method of adding hot water produces a milder version of original flavor, while passing more water through the load of ground coffee will add other flavors to the espresso, which might be unpleasant for some people.