Method for brewing coffee

A method to prepare a filter coffee with a full automatic coffee machine, the machine comprising a coffee extraction unit, the coffee extraction unit comprising:

• a brewing chamber for receiving roasted and ground coffee powder, the brewing chamber comprising an upper rim and a bottom wall,
• an upper piston configured to be movable through the upper rim of the brewing chamber and inside the brewing chamber further to the relative movement of the brewing chamber and the upper piston,
• a water inlet,
• a liquid outlet duct guiding extracted coffee beverage to a dispensing area,
• a lower piston movable inside the brewing chamber between:
• a lowest position wherein the lower piston lies at the bottom of the brewing chamber, and
• a highest position wherein the lower piston is at the upper rim of the brewing chamber,
• a discharge device for spent coffee,
• wherein the brewing chamber and/or the upper piston are relatively movable between:
• an open position for introducing the roasted and ground coffee powder or ejecting extracted roasted and ground coffee powder, where the upper piston is at a distance from the upper rim of the chamber and outside the chamber, and
• different closed positions configured for brewing the roasted and ground coffee powder, and
• a water fluid system comprising at least a water supply, and a water pump, wherein the water fluid system is connected to the water inlet of the coffee extraction unit,
• wherein the method comprises the steps of:
• a—obtaining beverage selection input for the filter coffee from a user about a type of preparation of the filter coffee in the list of at least a pressurized coffee and the filter coffee, then
• b—in the open position of the brewing chamber and the upper piston, supplying a dose of the roasted and ground coffee powder in the brewing chamber, the dose of the roasted and ground coffee powder defining a volume inferior to the largest possible closed volume of the brewing chamber, then
• c—moving the brewing chamber and the upper piston relatively one to the other to one closed position without compacting the dose of the roasted and ground coffee powder, then
• d—supplying pumped water through the water inlet, extracting the roasted and ground coffee powder and dispensing the extracted coffee beverage through the liquid outlet duct, then
• e—compacting the extracted roasted and ground coffee powder inside the brewing chamber, then
• f—discharging the extracted roasted and ground coffee powder from the brewing chamber,
• wherein all along step d), the pumped water is continuously supplied in pulses.