Straight ristrettos—shots that are traditionally drunk from a demitasse and not diluted into a larger cup containing milk or water—could be described as bolder, fuller, with more body, and less bitterness, but with a higher concentration of acidity. These characteristics are usually attributed to espresso in general but are more pronounced in a ristretto. Diluted into a cup of water (to make an Americano or long black) or milk (e.g. latte and cappuccino), ristrettos are less bitter and exhibit a more intense espresso character.
Moka coffee is coffee brewed with a moka pot, a stovetop coffee maker which produces coffee by passing hot water pressurized by steam through ground coffee at a lower pressure than an espresso maker. The moka pot is an Italian invention, first produced by Bialetti in the early 1930s. The flavor of moka pot coffee depends greatly on bean variety, roast level, fineness of grind, and the level of heat used. Due to the higher-than-atmospheric pressure involved, the mixture of water and steam reaches temperatures well above 100 °C, causing a more efficient extraction of caffeine and flavors from the grounds, and resulting in a stronger brew than that obtained by drip brewing.
Ristretto is traditionally a short shot of espresso made with the normal amount of ground coffee but extracted with about half the amount of water. Since ristrettos are essentially the first half of a full-length extraction, the faster-to-extract compounds predominate in a ristretto. The opposite of a ristretto is a lungo, which is typically double the shot volume. Ristretto means “limited” or “restricted” in Italian whereas lungo means “long.”