In the coffee home-countries (namely, Ethiopia and Yemen, and other Middle East countries), the "early coffee beverage" was brewed using the whole coffee cherry or berry as it was after being picked up from the coffee plants, and then simply pounded; later, only the coffee green beans contained in the cherry were used. Apparently, the raw or green coffee beans were not roasted until the Thirteenth century; however, the coffee beverage was still prepared by boiling the whole roasted beans.

The following step was that of grinding the roasted beans into a powdered form by simply using the pestle and mortar, and then boiling in the water the ground coffee so obtained together with honey and various spices. The brew was then consumed soon after the coffee dregs sank in the cup.

The first tools used for the preparation of coffee, from the pan or cylindrical coffee roasters to the mortars and coffee grinders to reduce the roasted coffee into powder, started to be manufactured around the mid of the seventeenth century.  The first coffeepots in copper and brass, finely hand-chiseled and decorated, were then produced in a conic, bulb or amphora-alike form. From Turkey to Syria, from Tunisia to Morocco, the coffee was brewed by using the so-called “Ibrik”, “Cezve”, “Dellel” or “Rakwa”.

At this time, the coffee arrived in Europe and its home preparation would imitate the procedure used in the coffee home-countries; tinplate coffeepots called “Cuccume” or“Bricchi” or more refined coffeepots made in copper, brass, pewter or silver called “Samovar”  were largely used. With the boiling system a quite dense and sour beverage with coffee dregs in the cup was obtained. These features and the high cost of the product did not really appealed to the "Old World" and this did not favor the coffee spreading and consumption.

This was the start of a 3-century period of breakthroughs and inventions, tests and experimentation in the attempt of questing for the ideal system to brew the black beverage, so that the whole flavor of the roasted bean could remain intact and become full-bodied while sipping it.

However, given the limited knowledge of the chemical-physical-organoleptic properties of the product, brewing a good cup of coffee implied a serious of problems, also considered the numerous variables inherent to its preparation such as the quality of the raw coffee bean, the roasting uniformity and duration, the conservation, the type and degree of grinding, the quality, temperature and pressure of water, the infusion duration, and the ratio between the quantity of water and ground coffee to be used.

It is important to understand how all these variables may interact in the brewing process; for this reason, we try to explain the following interactions in brief:

Roasting and conservation. Raw coffee must have a homogeneous quality and it is essential to pay particular attention to the stocking in order not to deteriorate its quality due to humidity and mould. To have a homogeneous tasteful coffee, the coffee beans must be roasted uniformly, that is to say having all the same temperature and undergoing the same roasting interval. This property is made evident by the homogeneous color of coffee beans, which must be the same both internally and externally. Coffee must be of a fresh quality, as a stale coffee may modify its flavor and be ground differently as it becomes softer with ageing.

Grinding. The more finely the coffee is ground and the fastest it releases its flavor in a complete manner; however, once it has been ground, the coffee accelerates the ageing process. Yet, the more finely the coffee is ground, the highest is the resistance to water filtering. Thus a device for creating a higher water pressure (compared to the external atmospheric pressure) is required for the water percolating through it.

Infusion. In order to obtain a perfect and complete coffee extract, whatever is the coffee machine used, it is necessary to completely dip the ground coffee into water, accurately preventing any leakage from the coffeepot or machine, notwithstanding the increasing volume. If the infusion time is higher than the time required, the bitter taste is accentuated, while, if it is lower, the coffee is not completely extracted and results to be "lighter".

Water temperature. The extraction of the coffee aroma varies according to the infusion water temperature. The correct service temperature varies between 92 to 96° C, both for filter coffeepots and for espresso coffee machines. If the temperature is close to the boiling point, the coffee tends to become bitter; if it is too low, the coffee is under-extracted in the aroma and thus less tasteful.

These basic concepts are fundamental for the brewing of a good coffee.
However, the first inventors who tried to create coffee machines knew very little about the basic properties and chemical-physical relations of coffee to make roasting, grinding, infusion, temperature and water pressure coherent. It was during the Nineteenth century that the main technological solutions were designed, patented, built up (and then modified), and marketed for the extracting of the black beverage, including the first household coffee machines.

Across Europe, from the early 1800, dozens of engineers, tinsmiths and silversmiths, but also inventors and housewives competed among each other for the discovery of the "perfect coffee machine" producing the best coffee, being easy to handle, reliable and automatic. The principles of liquid physics, thermodynamics, vacuum, steam and hydrostatics were applied and experimented. 

Many ideas and projects have remained unchanged so far, as they have never been thrown away from the registry offices for patents. Some of the inventors proposed solutions which the technology of those years could realize in a reliable manner. Other machines included complex devices requiring professional skills for their handling, which could cause fire or explosions in case of human errors. Some of them added useless devices, which further made their functioning more complicated.

The various typologies of coffee machines having in time a certain marketing impact - so that they were produced and used at home at least for some decades - may be grouped in the following ten typologies on the basis of its system and functioning method:

Boiling.  Also known as the“Turkish style”, the beverage is prepared in a simple coffeepot by boiling water together with ground coffee.

Percolation or filter. The filter or percolation coffeepots represent the first step of the coffee machine evolution in the brewing of coffee compared to the previous boiling methodology. Hot water is poured into the coffeepot through the coffee powder (percolation) contained in a small cloth bag or in a metal mesh basket (filter).
 
Upside-down percolation. The coffeepot is divided into two compartments, lower and upper,  which are united by the filter containing the coffee powder.  The water is boiled in the lower compartment; then the pot is turned upside down allowing the water to percolate through the ground coffee into the other compartment.
 
Pump percolation. From the boiler, the water is pumped up through the filter containing the coffee powder. The infusion is then collected into a separated compartment to be poured into the cup. This cycle is carried out only once.

Percolation with recirculation pumping. In the coffeepot, the water is pumped up to the surface to percolate through the ground coffee and then be collected into the same coffeepot by means of a continuous circulation until the heat source is removed.
 
Piston or filter-press. After some minutes the coffee powder has been infused into the boiling water, the piston with filter is pushed downwards to press over the ground coffee at the bottom of the coffeepot and to separate the coffee dregs from the beverage.
 
Hydrostatic percolation. The hot water is poured into the central telescopic pipe of the coffeepot, then mixing with the ground coffee contained in the filter at the basement; in this system, the water column pressure is exploited. The basic idea is that of providing more pressure to the water (compared to the force of gravity) during the percolation through the coffee filter, to extract the aroma to its best.
 
Vacuum or depression system. The simplest form coincides with two glass balls, one placed over the other and connected through a filter. The steam pressure makes the water contained in the lower ball go up, then mixing with the coffee powder contained in the upper ball. When the heat source is removed, the air in the lower glass ball is cooled down creating a vacuum which immediately sucks the coffee infusion of the upper glass ball; percolating through the filter, the coffee infusion dregs are blocked before entering the lower glass ball.

Steam pressure (long espresso coffee). In the steam-pressure coffeepots, the hot water is pumped by the steam force (pressure) to percolate through the coffee powder pressed into the filter. In the previous percolating systems, the only exploited force was the gravity.
 
Piston or pump pressure (strong espresso coffee). In this typology of coffee machines, the hot water is percolated through the ground coffee pressed into the filter by means of a lever piston or pump.