A coffee maker is a small heating appliance designed for brewing coffee from ground coffee beans without having to boil water in a separate container.
Types of Coffee Maker
The different types of coffee makers are:
Percolator style coffee maker
Drip-brew or a drip coffee maker
Electric or a automatic drip coffee maker
coffee maker
Siphon Coffee maker and
Pour-over or water displacement drip coffee maker
Percolator Type coffee maker
A coffee percolator is a type of pot that is used to brew coffee. The word percolator is originated from the word “percolate” that means to allow water to pass through the coffee grounds for extracting coffee that give its color, taste and aroma. Today, in the market, one can find different types of percolators, depending on the source of heat.
Electric Coffee Percolator is the most common type. It is much more popular than its counterparts, as it gives a more consistent brew by stopping automatically when the coffee is done. It then switches to a warming mode when completed. An electric percolator has a built in heating element that can be cordlessly used.
Construction
Percolator type coffee maker consists of a pot with a small chamber at the bottom which is placed closest to the heat source. A vertical tube leads from this chamber to the top of the percolator. Just below the upper end of this tube is a perforated chamber.
In the base of the coffee maker will find the resistive heating element (a wire coil that becomes hot when electricity flows through it), which comes in direct contact with the bottom of the warming plate. It is coated in thick, white grease that conducts heat, spreading it out evenly. The resistive heating element is controlled by the on/off switch and, while it’s on, managed by sensors. A simple percolator type is shown in Fig.
Operation of coffee maker
The desired quantity of water is poured into the water chamber of the pot and the desired amount of a fairly coarse-ground coffee is placed in the top chamber. It is important that the water level be below the bottom of the coffee chamber. When the supply is given to the heating element, the temperature rises until the water in the bottom chamber boils. While some models may have a one-way aromalock valve at the bottom of the tube which forces some of the boiling water up the tube, most operate on the simple principle that the rising bubbles will force the liquid up the tube.
The hot water is distributed at the top over the perforated lid of the coffee chamber. This water then seeps through the coffee grounds and leaves the coffee chamber through the bottom, dropping back into the lower half of the pot. The rest of the colder water at the bottom is meanwhile also forced up the tube, causing this whole cycle to repeat continually.
As the brew continually seeps through the grounds, the overall temperature of the liquid approaches boiling point, at which stage the “perking” action (the characteristic spurting sound the pot makes) stops, and the coffee is ready for drinking.
Drip Coffee maker
This type simulates the working of a manual drip coffee brew, where a filter containing the grounded coffee is placed over a carafe and hot water is poured over the coffee ground and then, passing through the filter, drips as coffee into the carafe. This can be done manually or by using an electric or automatic drip coffee maker. An average size for a drip brew coffee maker would be a 12 cup coffee maker.
Automatic drip coffee maker
In automatic type, Water from a cold water reservoir passes through a flexible tube into a heating chamber where the water is heated, a thermostat prevents that it is heated too much and converted into steam. This heated water gets moved up towards a spray head from where it drips down onto the ground coffee. This coffee is normally contained in a, paper or gold, filter hold by a container, which is located below the spray head. The water passes through the filter, the coffee and than drips into a glass or thermos carafe. When brewing more as 12 cups coffee a more powerful heating element is necessary.
