Ristretto
Ristretto is a very "short" shot of espresso coffee. Originally this meant pulling a hand press (shown at right) faster than usual using the same amount of water as a regular shot of espresso. Since the water came in contact with the grinds for a much shorter time the caffeine is extracted in reduced ratio to the flavorful coffee oils. The resultant shot could be described as bolder, fuller, with more body and less bitterness. All of these flavors are usually attributed to espresso in general, but are more pronounced in ristretto. Today, with the hand press out of favor and modern automated machines generally less controllable, ristretto usually just means less water; a double espresso shot is typically around 60 ml (2 fl oz), while a double ristretto is typically 45 ml (1–1.5 fl oz).
Read more about this topic: List Of Coffee Beverages