For hundreds of years, making a cup of coffee was a simple process. Roasted and ground coffee beans were placed in a pot or pan, to which hot water was added, followed by attachment of a lid to commence the infusion process. Pots were designed specifically for brewing coffee, all with the purpose of trying to trap the coffee grounds before the coffee is poured. Typical designs feature a pot with a flat expanded bottom to catch sinking grounds and a sharp pour spout that traps the floating grinds. Other designs feature a wide bulge in the middle of the pot to catch grounds when coffee is poured.
Carafe style. Heavy coffee drinkers should look for a model with a thermal carafe. These coffee machines can keep your coffee warm for hours without having to sit on a burner, which can scald the liquid. Glass pots are not insulated and must sit on a heated burner to keep the coffee warm, so they’re an ideal choice for those who need only one or two cups a day. Some coffee drinkers insist that a glass carafe results in a better-tasting cup of joe.
An electric drip coffee maker can also be referred to as a dripolator. It normally works by admitting water from a cold water reservoir into a flexible hose in the base of the reservoir leading directly to a thin metal tube or heating chamber (usually, of aluminum), where a heating element surrounding the metal tube heats the water. The heated water moves through the machine using the thermosiphon principle. Thermally-induced pressure and the siphoning effect move the heated water through an insulated rubber or vinyl riser hose, into a spray head, and onto the ground coffee, which is contained in a brew basket mounted below the spray head. The coffee passes through a filter and drips down into the carafe. A one-way valve in the tubing prevents water from siphoning back into the reservoir. A thermostat attached to the heating element turns off the heating element as needed to prevent overheating the water in the metal tube (overheating would produce only steam in the supply hose), then turns back on when the water cools below a certain threshold. For a standard 10-12 cup drip coffeemaker, using a more powerful thermostatically-controlled heating element (in terms of wattage produced), can heat increased amounts of water more quickly using larger heating chambers, generally producing higher average water temperatures at the spray head over the entire brewing cycle. This process can be further improved by changing the aluminum construction of most heating chambers to a metal with superior heat transfer qualities, such as copper.