There are four main methods of brewing coffee. The main differences in these methods are the ways in which water is combined with the coffee grounds. These methods involve boiling, pressure, gravity, and steeping. Espresso is made using pressure. Plain American coffee can be made using any of the other three methods.
Basically, brewed coffee is made by combining coffee grounds with hot water. With the exception of Turkish coffee, the coffee grounds are either left behind (in the coffee brewing machine), or are filtered out of the finished coffee after the soluble components have been extracted from the coffee grounds. Different coffee-brewing methods require different grinds of coffee.
In Europe and America, the usual ratio of coffee to water used in brewing is between one and two tablespoons of ground coffee per six ounces of water. Real coffee lovers tend to like their coffee at the higher-end of this scale: two tablespoons of ground coffee per six ounces of water.
Once coffee is brewed, its flavor will start to deteriorate as it cools to room temperature. Hence, we recommend using a hot plate to keep the coffee warm if it is to be held prior to serving. Of course, this does not apply to iced-coffee beverages, where the coffee flavor is best captured by cooling the coffee (well below room temperature) as quickly as possible.
This is a misnomer, since the coffee grounds are not actually boiled. Boiling the coffee would result in an inferior bitter coffee brew. Nonetheless, the "coffee boiling" method is so-called because it is the simplest method. The coffee boiling method is as follows.
The coffee grounds are placed in a cup or other vessel, and hot (or near-boiling) water is poured over them. The coffee grounds steep in the water until the coffee mixture has cooled enough to drink. (This is exactly how tea is prepared as well.) By the time that the coffee reaches a drinkable temperature, the coffee grounds will have sunk to the bottom of the cup. The coffee can be drunk directly (while being careful not to drink the coffee grounds), or it can be strained first.
This style of coffee was once called "Cowboy Coffee," since it probably originated around a campfire, and is simply made with a pot of boiling water and some coffee grounds. Some coffee lovers actually prefer this method.
Turkish coffee is also made by using the boiling method. In the case of Turkish coffee, the coffee beans are ground or pounded into a fine coffee powder. The finely ground coffee powder is placed into a narrow-topped pot called an "ibrik" (in Arabic) or "cezve" (in Turkish). Water is added, and sugar is traditionally added as well. The mixture is brought to a boil very quickly, and then immediately removed from the heat. In Turkish coffee, cardamon can also be added to the coffee mixture.
This method is used for espresso. Espresso is made with nearly boiling water (about 200 degrees F), which is forced under pressure (8-9 atmospheres) through a "puck" of finely ground coffee. Espresso has a very strong coffee flavor, and is a basis for many coffee drinks.
In a moka pot, water is boiled in the lower section, and then it is forced up (by steam pressure) through the coffee grounds, which are located in the middle section of the pot. The coffee is collected in the upper chamber where it condenses. Coffee brewed in this way is almost as strong as espresso.
A vacuum coffee brewer has two chambers: a pot, and a bowl which sits above the pot. The water is placed in the pot and the coffee grounds are placed in the bowl. The brewer is set on a burner. As the water heats, it is forced up into the bowl by vacuum pressure, where it mixes with the coffee grounds. When all the water has been vacuumed into the bowl, the brewer is removed from the heat. As the mixture cools, the coffee is forced back down into the pot through the filter. The bowl can then be removed, and coffee is served directly from the pot.
Filter brewing (drip brewing) is the method typically used by most American home coffee makers. Coffee grounds are placed into a filter basket, and heated water is dripped into the basket, where it mixes with the coffee grounds, and then drains through the coffee filter. This produces what most Americans drink as "coffee." It is much less pronounced than espresso.
An electric percolator uses a hybrid method containing aspects of both the gravity and pressure methods. This was the common method for brewing coffee in the home several decades ago. Water is placed in the lower chamber of the percolator, and coffee grounds are placed in a filter basket in the upper chamber of the percolator. As the water is brought to a boil, pressure forces it upwards (usually through a central stem) where it drips into the coffee grounds, filters through them, and returns to the lower chamber. The coffee is allowed to "percolate" in this manner for a fixed period of time, with the coffee liquid making multiple passes through the coffee grounds.
Today, percolating coffee is not thought to be the best method. The problem with it is that the coffee is essentially boiled throughout the duration of the process, which can impart a bitter taste to the coffee.
The French press (cafetière), or "press pot" is a tall narrow glass cylinder with a plunger that contains a filter plate. Coffee grounds are placed into the cylinder, hot water is added. The coffee grounds are left to steep in the water for 4 or 5 minutes, and then the plunger is depressed. The filter plate forces the coffee grounds to the bottom of the cylinder, which leaves strained coffee in the top.
This considered by many people to be the ideal method of making the coffee at home. Today, there are small portable press pots that are suitable for making coffee on the way out the door in the morning. The plunger can be pushed once on the road, and the coffee can be drunk directly from the press pot.
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The Coffee Brewers
The Coffee Boiling Methods
The Pressure Brewing Methods
The Gravity Brewing Methods
The Steeping Method