COFFEE MAKING PROCESS
Coffee can be brewed in several different ways, but these methods fall into four main groups depending upon how the water is introduced to the coffee grounds. If the method allows the water to pass only once through the grounds, the resulting brew will contain mainly the more soluble components (including caffeine), whereas if the water is repeatedly cycled through the beans (as with the common percolator), the brew will contain more of the relatively less soluble compounds found in the bean; as these tend to be more bitter, that type of process is less favored by coffee aficionados.
Drip brew (also known as filter or American coffee) is made by letting hot water drip onto coffee grounds held in a coffee filter (paper or perforated metal). READ MORE...
Espresso is made with hot water at between 91 °C (195 °F) and 96 °C (204 °F) forced, under a pressure of between eight and nine atmospheres (800-900 kPa), through a tightly packed matrix (called a puck) of finely ground coffee. READ MORE...
Despite the name, care should be taken not to actually boil the coffee (or at least not for too long) because that would make it bitter. READ MORE...
A cafetiere (or French press) is a tall, narrow glass cylinder with a plunger that includes a wire mesh filter composed of metal or nylon. READ MORE...
Coffee in all these forms is made with coffee grounds (coffee beans that have been roasted and ground) and hot water, the grounds either remaining behind or being filtered out of the cup or jug after the main soluble compounds have been removed. The fineness of the grind required differs by the method of extraction.
Water temperature is crucial to the proper extraction of flavor from the ground coffee. The recommended brewing temperature of coffee is 93 °C (199.4 °F). Any cooler and some of the solubles that make up the flavor will not be extracted. If the water is too hot, some undesirable elements will be extracted, adversely affecting the taste, especially in bitterness.
The usual ratio of coffee to water for the style of coffee most prevalent in Europe, America, and other Westernized nations (evident in publications such as textbooks on coffee and instruction manuals for drip-brew machines) is between one and two tablespoons of ground coffee per six ounces (180 millilitres) of water; the full two tablespoons per six ounces tends to be recommended by experienced coffee lovers. Note that the size of the grinds has an effect on the strength and the amount of coffee needed and may need to be adjusted accordingly.
Brewed coffee continually heated will deteriorate rapidly in flavor; even at room temperature, deterioration will occur. For this reason aficionados frown upon the hotplate which is sometimes used to keep brewed coffee warm prior to serving. However, if it is kept in an oxygen-free environment it can last almost indefinitely at room temperature, and sealed containers of brewed coffee are sometimes commercially available in food stores in America or Europe, with Frappuccino being commonly available at convenience stores and grocery stores in the United States.
Electronic coffee makers boil the water and brew the infusion with little human assistance and sometimes according to a timer. Some even grind the beans automatically before brewing.