The lever extraction system.
The lever system of this professional coffee machine lets the barista modulate the pre-infusion manually for each delivery. When you lower the lever hot water from the boiler enters the group, wetting the coffee. The more the barista pulls the lever, the longer the pre-infusion phase. A good professional waits for the first drops of coffee to come out before lifting the lever; this means that water will have permeated all the coffee. For effective pre-infusion, the pressure of the water as it enters the group should not exceed 2 bars.

Technology meets the lever espresso machine.
n typical lever espresso coffee machines the water that enters the group is straight from the boiler, which is well known to have a pressure of 1 to 1.2 bar, corresponding to 120-130° C. Basically it is the same water used to generate steam. Instead, in the Victoria Arduino VA358 White Eagle, which uses heat exchangers (even though it is a lever machine), the water temperaturecan be controlled to optimize the quality of extracted coffee. In this case, for an excellent pre-infusion, a special pressure reducer reduces the pressure of the water supply, which is normally 4 to 6 bar. With these specifications, coffee extractions with the VA358 White Eagle are particularly creamy and not burnt (as may happen with water at high temperatures).