Inside the RD-LE6400: why RADOCO chose an Italian ULKA pump

Retro espresso machines are usually bought for their looks. RADOCO wanted the RD-LE6400 to be bought again for its coffee — and that comes down to one part most buyers never see: the pump.

The RD-LE6400 uses a 15-bar vibratory pump made by ULKA in Italy, the same family of pumps found in machines several times its price. "A pump that delivers stable pressure through the whole shot is what separates a real espresso from a strong coffee," the product team says. "Cheaper pumps peak and fade. This one holds."

The second decision was pre-infusion. Before full pressure, the machine wets the coffee puck at low pressure for a moment. It lets the grounds swell evenly so water does not find a fast channel through one side — the most common cause of a sour, thin shot at home. It also makes the machine more forgiving of an uneven tamp.

Around the pump sit a 1350 W thermoblock, a 1.5 L removable tank and a steam wand that produces the dry steam needed for microfoam. The shell is enamelled steel in glossy black or cream, with a 2-year guarantee.

Learn the method in how to make espresso at home with a 15-bar machine.