A coffee maker is a very simple, low-tech, yet efficient machine. A heating element circles the hot plate at the bottom of the maker. Wrapped in this heating element is a hollow aluminum tube. When water is added to the reservoir, a small hole in the bottom of the container feeds a plastic hose that leads down to one end of the aluminum tube. Once the coffee pot is switched on, the heating element gets hot very quickly. Sensors cycle the element on and off to keep it 195-205 degrees Fahrenheit (90-96 Celsius). Water sitting in the aluminum tube boils and the turbulence creates bubbles that rise though the opposite end of the tube, traveling up an exit hose (making room for more water to enter the heating element). Hot water riding on these rising bubbles creates upward lift that carries a small stream of boiling water to the top of the coffee maker. Here the exit hose terminates on to a drip plate. The drip plate distributes the boiling water evenly to fall through to the coffee grounds below in the filter basket. Hence, the drip coffee maker fills the carafe with freshly brewed java.
If you buy coffee beans whole you can use a coffee grinder to prepare them. It is best to grind the beans just prior to brewing. A drip coffee pot uses medium to coarsely ground coffee, while finely ground coffee is used for making espresso. Note that espresso cannot be brewed in a drip coffee maker, but is made in an espresso machine.
Most coffee pots have a timer allowing them to turn on automatically. Some people prefer to prepare their coffee maker at night, setting the timer so they can wake to freshly made coffee in the morning. Though this is convenient, connoisseurs would not only object to grinding the coffee beans so many hours in advance, but would also point out that once the coffee is brewed it should be taken off the hot plate. Continued exposure to heat will bring out harsher flavors including bitterness.
Some coffee pots use steel filters, others use paper filters. Steel filters will allow more oils to pass, making coffee that is headier and has more body. Paper filters create cleaner, lighter coffee.
Experts say evidence suggests coffee arabica originated in Ethiopia and has been cultivated for about 1500 years. Though coffee is brewed many different ways all over the world, today the coffee maker is by far the most popular way to brew a cup of Joe.