A lever-operated espresso machine utilizes a spring-piston mechanism activated by a hand lever to generate the pressure required for brewing. This direct control over pressure profiling allows the barista to manipulate the extraction process, influencing the flavor profile of the resulting espresso. A classic example involves raising the lever to pre-infuse the coffee grounds and then gradually lowering it to control the flow of water through the coffee puck.
This hands-on approach offers a unique level of engagement with the brewing process and often results in a richer, more nuanced espresso. Historically, lever machines were the predominant style of espresso makers, preceding automated pump-driven systems. The resurgence in their popularity reflects an appreciation for the craft of espresso making and the potential for greater control over flavor extraction.