This method produces coffee very similar to the early "espresso" that became popular in Italy during the first half of the 20th century. Hot water is forced through coffee grinds by the steam pressure, producing a strong, concentrated cup of coffee.
Present day espresso forces the coffee through the grinds at much higher pressures using pumping devices. This higher pressure creates a cup of coffee significanly different than Moka coffee. More flavors and oils are extracted. This can be seen in the emulsion ("crema") that caps the drink. This "true espresso" brewing came into being only towards the middle of the 20th century and has been popularized in coffee bars and for home use during the last years of the 20th century.
Moka Brewing might be better labeled as steam-pressure brewing but the Moka Pot is the most prevalant application used. This method uses a brewer that consists of:
The Bialetti company of Omegna, Italy has done the most to popularize this method of brewing and has developed a new model that claims to extract some oils and flavors similar to coffee brewed in the true espresso fashion.