Ristretto
Ristretto, known in full in Italian as caffè ristretto, is a "short shot" of a highly concentrated espresso. It is made with the same amount of ground coffee, but extracted using half as much water. A normal short shot might look like a ristretto, but in reality, would only be a weaker, more diluted, shot. The opposite of a ristretto is a lungo, which has double the amount of water. In France a ristretto is called café serré.
Regardless of whether one uses a hand-pressed machine or an automatic, a regular double shot is generally considered to be around of ground coffee extracted into about 40 ml. Thus, a "double ristretto" consumes the same amount of coffee beans but fills only a single shot glass.
Coffee contains over a thousand aromatic compounds. A ristretto's chemical composition and taste differ from those of a full-length extraction for three reasons:
- More concentrated: the first part of any extraction is the most concentrated, its color typically lying between dark chocolate and umber, whereas the tail end of shots are much lighter, varying from the color of dark pumpkin pie to varying shades of tan. This is an important factor when drinking straight espresso shots.
- Different balance: different chemical compounds in ground coffee dissolve into hot water at different rates. A ristretto contains a greater relative proportion of faster extracting compounds, proportionally fewer of the compounds characteristic of over-extraction, and thus, a different balance.
- Fewer total extracts: relative proportions aside, fewer total coffee compounds—caffeine being just one—are extracted into ristrettos versus full length shots. This is an important factor when diluting shots into water or milk.