The Preparation of Coffee

Whole coffee beans have to be ground before making a cup of coffee. The fineness of grind must be matched to the brewing method for the best results Brewing methods which expose coffee grounds to heated water for longer require a coarser grind than faster brewing methods. If a too fine a ground is used a bitter, harsh taste may results. At the other extreme, an overly coarse grind will produce weak coffee unless more is used. Uniformly ground coffee is better than the mixture of sizes produced by a mill with chopping blades. Ground coffee deteriorates faster than roasted beans so it is best of grind the beans immediately before brewing.

Coffee may be brewed by several methods: boiled, steeped, or pressured. Brewing coffee by boiling was the earliest method, and Turkish coffee is an example of this method. It is prepared by powdering the beans with a mortar and pestle, then adding the powder to water and bringing it to a boil in a pot called a cezve or, in Greek, a briki. This produces a strong coffee with a layer of foam on the surface.

Machines such as percolators or filter coffee makers brew coffee by gravity. In a filter coffeemaker hot water drips onto coffee grounds held in a coffee filter made of paper or perforated metal, allowing the water to seep through the ground coffee while absorbing its oils and essences. Gravity causes the liquid to pass into a carafe or pot while the used coffee grounds are retained in the filter. In a percolator, boiling water is forced into a chamber above a filter by pressure created by boiling. The water then passes downwards through the grounds due to gravity, repeating the process until shut off by an internal timer.

Cafetiere is a coffee brewing device consisting of a narrow cylindrical jug usually made of glass or clear plastic, with a lid and a "plunger" which fits tightly in the cylinder. The end of the "plunger" has a fine wire or nylon mesh which acts as a filter. Coffee is brewed by placing the coffee and water together in the jug, leaving to brew for a few minutes, then depressing the plunger to push the coffee to the bottom of the jug. Coffee for use in a Cafetiere should be of a consistent, coarse grind. The use of a burr mill grinder gives a more consistent grind than the whirling blade variety. The coffee produced is usually stronger and thicker and has more sediment than filter-brewed coffee.

Espresso is made with hot water forced, under pressure through a lightly packed matrix (called a puck) of finely ground coffee. It can be served alone but it is also the basis for many coffee drinks. It is one of the strongest tasting forms of coffee regularly consumed, with a distinctive flavour and crema, a layer of emulsified oils in the form of a colloidal foam standing over the liquid.

Espresso-based coffee has a wide variety of possible presentations. In its most basic form, it is served alone as a "shot" or in the more watered down style café américano; shot or two of espresso with hot water. The Americano should be served with the espresso shots on top of the hot water to preserve the crema. Milk can be added in various forms to espresso: steamed milk makes a caffè latte, equal parts espresso and milk froth make a cappuccino, and a dollop of hot, foamed milk on top creates a caffè macchiato.

Instant coffee is dried into soluble powder or freeze dried into granules that can be quickly dissolved in hot water.