How a Stove-top Espresso Maker Works

The science behind espresso making is concerned with applying a greater amount of pressure, or force on the coffee grounds then normal gravity, in order to extract more of the coffee's flavour. Numerous studies have shown that to achieve that 'god shot' of espresso, coffee grounds need to be subjected to between 130-150psi (9-10 bar) of pressure.

Although stove-top espresso makers operate under a much lower pressure, typically 15psi (1 bar), they still generate enough pressure to make great-tasting espresso style coffee. Recent advancements in stove-top technology, such as that used in the Bialetti Brikka and Mukka Express have increased this amount of pressure to just under 36psi (2.5 bar) for even greater coffee extraction.

• When you prepare your stove-top espresso maker for use, air gets trapped inside the water tank.




• When heat is applied to the stove-top espresso maker, the air and water inside expand. As they are contained within the water tank, this leads to a build up of pressure in the tank.
  
  



• Eventually, the pressure builds up to the point where the hot water is forced up through the coffee in the filter basket into the upper chamber of the stove-top espresso maker.