The "Moka" is the typical Italian Coffee maker, and is
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".
Mokas come with different sizes, from one to eighteen 50 ml
cups.
Brewing coffee with a 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 above. 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".
