The moka pot is a stove top espresso coffee maker, based on the principle of preparing coffee with steam pressurized water. First patented by Alfonso Bialetti in 1933, his company Bialetti continues to produce the same model known as the "Moka Express".

The moka pot is most commonly used in Europe, and has become known as an iconic design, displayed in modern industrial art museums, such as the Science Museum in London. Mokas come in different sizes, from one to eighteen 50 ml cups.The original design was made from aluminium with bakelite handles.

Brewing coffee with Moka

Water is poured in the boiler (marked A in the diagram) and the funnel-shaped metal filter (B) is inserted. Finely-ground coffee is added to the filter as shown below. The upper part (C, which has a second metal filter at the bottom) is tightly screwed on the base. By placing the pot on a heat source, the water is brought to boiling point creating steam in the boiler. A gasket ensures a tightly

closed unit and allows for pressure to safely build up in the lower section, where a safety valve provides a necessary release in case this pressure should get too high (with clean filters, that should not happen).

The steam eventually reaches a high enough pressure to gradually force the surrounding boiling water up the funnel through the coffee powder and into the upper chamber (C), where the coffee is collected. When the lower chamber is

almost empty, steam bubbles mix with the upstreaming water, producing a characteristic gurgling noise.

As with percolators, the pot should not be left on the stove so long that the coffee boils. Ideally, with a little practice, it should be removed from the heat before it actually starts gurgling - usually, when only about half of the top chamber has been filled.

Moka coffee vs. drip coffee

The flavour of stovetop espresso coffee depends greatly on bean variety, roast level, fineness of grounds, and the level of stovetop heat used. Due to the higher pressures involved, the mixture of water and steam reaches temperatures well above 100°C, causing a more efficient extraction of caffeine and flavours from the grounds, and resulting in a much stronger brew when compared to that obtained by drip brewing.

Moka coffee vs. espresso coffee

Moka pots are sometimes referred to as stove top espresso makers and produce coffee with an extraction ratio similar to that of a conventional espresso machine. Depending on bean variety and grind selection, Moka pots can create the same foam emulsion, known as crema, that conventional espresso machines can. They are commonly found in Italy, Spain and Portugal. They are also known as a macchinetta, Italian for "little machine".

Maintenance

Moka pots require periodic replacement of the rubber seal and the filters and a check that the safety release valve is not blocked.

After use, an often desired coat of oily coffee residue is left lining the interior of the stems, filters and upper chamber. This thin layer protects the coffee from contact with the aluminum wall, which might otherwise give a slight metallic taste to the coffee. This layer is only obtained by rinsing off the moka pots components with water only, instead of washing with added detergents.

Variations

Moka pots are normally made of aluminium for use over an open fire, or gas/electric range. However, several electric moka pots and stainless steel stovetop espresso machines are also available.

Brikka

Brikka is a modified mooney pot manufactured by Bialetti. It incorporates a weight on top of the nozzle that causes pressure to build up inside the water tank in a manner similar to old style pressure cookers. The result, while not espresso, is closer in terms of taste and crema foam to espresso than what a normal moka pot produces. Mukka Express is modified moka pot also manufactured by Bialetti that allows milk

to be frothed and mixed with the coffee during brewing. The name, 'Mukka', is a pun on the Italian for cow, 'mucca'.

Other brands

Alessi is another Italian manufacturer of Kitchen wares that is known for their moka pots. Bodum has added a " Chambord" stove top espresso maker to their line, which while differing in appearance is similar in function to the moka pot.