Espresso Machines

Pump-driven Espresso Machine

A refinement of the piston machine is the pump-driven espresso machine, which has become the most popular design in commercial espresso bars. Instead of using manual force, a motor-driven pump provides the force necessary for espresso brewing. Commercial or some high-end home machines are often attached directly to the plumbing of the site; lower-end home machines have built-in water reservoirs.

Home (consumer-grade) pump espresso machines typically use a single chamber both for heating water to brewing temperature, and to boil water for steaming milk. Since the optimum temperature for brewing coffee is much less than the temperature for creating steam, the machine requires time to make the transition from one mode to the other. Commercial-grade and “semi-commercial” high end home espresso machines use the boiler chamber only for making steam. Water for brewing most commonly passes through a heat exchanger (taking some heat from the steam, without rising to the same temperature). In a few commercial espresso machines (notably La Marzocco), water for brewing is heated in a separate chamber.

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